THE PRINCIPLES
of
PHYSIOLOGICAL AND PHYSICAL
SCIENCE;
COMPREHENDING THE ENDS FOR WHICH
Beings
WERE CREATED ;
and,
AN EXAMINATION
OF THE
UNNATURAL AND ARTIFICIAL
SYSTEMS
OF
PHILOSOPHY
WHICH NOW PREVAIL.
–
INTRODUCTION
NOTWITHSTANDING the boasted assertions
which are generally made, of the high degree
of perfection which, in these latter days, the
different branches of philosophy are supposed
to have attained it will, I fear, upon a fair
inquiry be found, that we continue in the very
infancy of our knowledge ; that, with the exception
of mathematical truths, and of those
arts which are founded on mathematical principles,
there subsists scarcely one subject,
either of physics, of metaphysics, or of physiology,
the science of which is clearly understood,
or, as to the truth of which an uniformity
of opinion subsists. The essential attributes
which different bodies possess, the first
and most simple elements of which they are
composed and the definitions by which those
elements are characterised, continue, to natural
philosophers, points ofconstant controversy and
disputation.
If we extend our views from the primary and
essential, to the secondary and accidental
qualities of matter, the last and most trifling
branch of natural philosophy, to which the
province of chemistry more especially beX*
INTRODUCTION.
longs ; we shall find, that although chemistry
has occupied the thoughts of, and been pursued,
with zeal the most ardent, by a great number
of learned and enlightened men in every
part of Europe, we, continue completely ignorant
of the principles on which chemistry, as a
science, is founded.
Without previous design, or by mere chance,
as it may be called, we have, it is true, discovered,
that when different substances, (such as
acids and alkalies, for example) are brought into
contact, an union between them takes place ;
we are by experience taught, that different bodies
have a stronger disposition to unite together,
to the exclusion of others with which they
may have been combined ; but of the cause
why these separations are produced, and new
combinations formed on what principle the
doctrine of elective attraction, or chemical affinity
is founded, wre are totally ignorant.
By the Researches of Professor DAVY, in the
art of chemistry, a multitude of opinions, which
by chemists had been received as fundamental
truths, have been overturned and exposed : he
has proved that a great proportion of the chemical
knowledge, not only of former times, but^
of the present day, is erroneous in some of its
most essential points; and it is now become a
common observation among our best chemists,
that in consequence of these new discoINTRODUCTION.
XI
veries, chemists will be probably obliged to
trace back the road of error which they have so
long traversed, in order to learn afresh the first
principles of their art/*
It is greatly to be lamented that the pursuits
of the chemists, instead of being confined to
their proper objects to the examination of the
qualities of matter, dead and common have
been equally, but improperly, directed and extended
to the investigation of living matter also ;
hoping to explore the causes of animation, and
of vital action, from chemical phenomena, which
are the inevitable attributes of decomposition
and decay.*
* The Monthly Magazine, some time since, very justly
observed,
” that Dr. DAVY’S Chemical Lectures shew, that
students in chemistry have to unlearn most of what they have
received as authority in that science. It may be hoped, therefore,
that we shall have no other voluminous systems of this
variable science> till its elementary principles are somewhat
better settled
”
* In deprecating, as I do, experiments, it is proper that I
should be clearly understood. I deprecate the application of
chemistry to physiology, as much as I would deprecate the
practice of employing the phenomena of death,^in order to
explain the actions of life ; and more especially I deprecate
the experiments made on different organs and fluids of the
living system, because the natural and healthy functions of a
part can never be ascertained through the medium of mutilation,
or extirpation; but%ith respect to the investigation of
matter dead and common, experiment alone is the medium
Xl INTRODUCTION.
It has been with this vain expectation, that
every solid and fluid, of which vegetables and
animals are composed, have been analysed with
the most accurate nicety; and effects, which
altogether depend on vitality and animation,
have been attempted to be explained, from the
result of decomposition and of death. To this
total inversion of all principle, with respect to
the relation which exists between things external
to the animated system, and the animated
system itself is to be ascribed the absolute
ignorance which prevails, not only of the function
of digestion, but of the operation of medicine
also ; not only of every organ, but of every
fluid of which the system is composed, Until
physiologists be made to feel that physiology is
still an art, not a science ; and pathologists,
that the practice of medicine is altogether empirical
; until the state of error and of ignorance
which exists, be truly and fairly represented, I
see no hope whatever of improvement, or of
reformation.
Much as there is to deplore with respect to
the application of physiology to practice, it is
through which its properties and attributes can be attained.
I think it proper to give this explanation, in order that it may
not be objected to me, that I reprobate experimental philosophy
in general, the odium of which, I am persuaded, would
otherwise be attempted to be fixed on me.
INTRODUCTION. X11I
sas a feather in the balance, when compared
with the relation which it is supposed to bear
to metaphysics. Instead of tracing the relation
which the different organs bear to each
other, as the means that are employed, with a
view to ends ; instead of exploring the nature
of life, and more especially of intellect, or of
soul, of that principle, by which man is more
especially characterised, from every other animal,
and by the proper exercise of which, he
is able to abstract himself from matter, and
from sense ; it is to the attributes of matter
alone, impelled by sensible objects, that the
existence f mind is generally ascribed ; and
by which the doctrine of materialism, in its
fullest extent, is attempted to be established.
Although the doctrine of materialism is not
proclaimed in our philosophical schools in
word, I will maintain, that it is so in deed.
I will maintain, that the existence of any
immaterial, or spiritual principle, is seldom,
if ever, mentioned, much less employed,
as constituting the cause of organisation,
or of intellection ; on the contrary, that
it is to the organisation alone, and to the
matter of which that organisation is composed,
that the principle of life and of mind, as
effects, is immediately referred. This evil
spirit, if it dared, would even manifest itself
XIV INTRODUCTION.
within the bosom of our universities. About
one year since, two members belonging to one
^>f the principal colleges in Oxford, published
a book, entitled,
” The Necessity of Atheism”
and they even had the audacity to attempt a
defence of the principles it contained, before
a convocation appointed to examine them.
These misguided men have been very pro-
-perly expelled the university, and the wretched
trash which they had written has been suppressed.
*
It has been the object of my most particular
solicitude to expose the errors of such
pursuits, and to point out the evils to which
they lead ; to show that such a system, instead
of leading to truth, not only recedes from it,
but perpetuates, and establishes, what is infinitely
worse than ignorance erroneous principles
: that instead of exploring the essential
properties of matter, with relation to the system
of order and subordination which exists
throughout the whole system of nature, se-
‘* I think it proper to mention this fact as an illustration*
more than as a proof, of the truth of my assertions. Whatever
blame might formerly be imputed to the laxity of University
morals, or University discipline, has been done away ;
there can be no cause of complaint now, the present system of
education bids fair to answer the ends for which it was originally
designed.
INTRODUCTION. XV
condary qualities alone obtained by artificial
means, are the objects of our present inquiries.
Instead of contemplating the attributes of the
Creator, from the works of creation, it is
through the medium of unnatural phenomena
alone, that natural phenomena are attempted
to be explained, I complain that the present
system of what is called philosophy, is an artificial,
not a natural one; and that the very
first dictum, or aphorism, proclaimed by LORD
BACON, in his NOVUM ORGANUM, is altogether
violated by our philosophers.
” Homo
Naturae minister et interpres, tanturn facit &
intelligit, quantum de naturae ordine, re vel
mente observaverit; nee amplius scit aut potest.”
I complain, that instead of making (as true
philosophy must ever tend to do,) man religious,
the present system is at variance with
religion, and deprives him of the benefits, and
of the comforts which religion is calculated to
bestow : that instead of leading man to God,
it estranges God from man, and separates, to
the utmost possible distance, (if I may be
allowed the expression,) the soul from the
Deity.
The Chapter which treats of Organic Life,
or the means by which the ends of existence
are attained, is, for the most part, a Syllabus
XVI INTRODUCTION.
of my NEW SYSTEM of PHYSIOWDGY,* which
was published in the year 1798.
* This work was first written with a view of exposing the folly
and errors of the Brunonian doctrine, which was, at that time,
in this country, as it still continues to be over different parts of
the continent, in general estimation. It is not likely that
any system of physiology, which took for its principle the
power of life, and the aptitude of matter which traced the
phenomena of vitality from organisation to action, and investigated
the particular organs, as the instruments by which
ends were obtained, would be very well received by those who
begin with death, and who end with life. Notwithstanding the
new opinions which it proclaimed, it was generally well spoken
of; and by the Medical and Chirurgical Review in particular,
it was observed,
” that in the execution of the extensive work
before us, Mr. SAUMAREZ is, in many parts, original ; it is,
however, but justice to add, that a passion for novelty does
not appear to have led him to a hasty adoption of opinions on
slight or trivial grounds. His arguments are, in general,
well supported, arid his conclusions cautiously deduced. As
a whole, it certainly bespeaks the industry and genius of a
writer who dares to think for himself, unfettered by prejudice
and authority, &c.” Again,
” we are not sorry to see the
errors of the Brunonian system thus combated by an able
champion ; it happens with this theory, more than with any
former one, that its errors are not merely speculative, but
lead to the greatest possible mistakes. Indeed it would be
no easy matter to calculate the mischief which it has occasioned
in the hands of young and inexperienced practitioners ;
but when we find, from Dr. BEDDOES himself, the translator,
its ascendency over men’s minds, in different parts of
Europe ; and that in the celebrated University of Pavia, there
is hardly a student endowed with talents, who is not a Brunonian,
it is surely high time to examine its principles and refute
its errors, &c. &c.
fr \ F^ S? )
CHAPTER I. ,> $ /
(\\ IVukV
ON THE PRINCIPLES OF SCIENCE.
IT is not my present intention to give an historical
detail of the rise and progress of scientific
knowledge, from the more remote periods of
antiquity, to its decline and fall during the
space of more than one thousand years, appropriately
denominated the dark ages. Knowledge
(if knowledge it may be called) was then
confined to the schoolmen ; the erroneous
practice, general at that period, of reasoning
without facts, and of drawing conclusions from
false principles, became at length apparent to that
great luminary of our country, LORD BACON.
The accumulation of error was, at that time,
too extensive to be corrected by any individual,
however mighty in intellect. Instead of unravelling
the gordian knot, he cut it. He did
not amuse himself with solving the most absurd
and ridiculous propositions that can be conceived
; with calculating, for example, how
2 PRINCIPLES OF SCIENCE.
many millions of angels could dance upon the
point of a needle ; but he determined to accumulate
facts only, before he generalised them ;
and thus was the art of induction raised upon
the ruins of false syllogism.
It is greatly to be deplored, that the plan
which he himself pursued, has not been adhered
to, by his followers in general ; and that attention
is not so much paid to the simple observation
of natural phenomena, as to those which
are the result of sophisticated experiments. I
do not decry experiments in general, it is the
abuse, not the use of them, which I reprobate
and condemn. It is through the agency of experiment,
that the useful arts have obtained so
high a degree of elegance and perfection ; that
chemistry, and what is called experimental
philosophy in general, are in a constant state of
improvement ; and that the certainty of many
uncertain things is ascertained. Let it not,
however, be supposed, it is on the result of experiment
alone that the whole of our knowledge
depends, or that it was so considered by Lord
Bacon himself; he expressly states that natural
history is the result of simple observation, and
classes it before experimental history. He considered
it the first means which ought to be employed
to accomplish the renovation, or, more
correctly speaking, the grand instauration of
science, as he terms it, which he had in view.
PRINCIPLES OF SCIENCE.
Had he been desirous of appealing to experiment
alone, he would have excluded the facts
which are the result of simple observation only.
If such had been his principles of learning, it
would have led, (as it has been well observed,)
to the unwarrantable length of supposing, that
knowledge could only be obtained through an
artificial, rather than through ^natural channel.
Assisted by the furnace and the crucible in the
laboratory, we should have been forced not to
use our eyes, unless with a candle in our hands
and spectacles on our nose and to withdraw
our senses from the knowledge which they convey
to the mind, of the undisturbed appearances
of nature.
Instead, however, of appealing to simple observation
for the apprehension of natural phenomena,
few phenomena are, at this time, supposed
or admitted to be true, unless proved by
the test of experiment ; unnatural effects are
generally preferred to those which are natural
and unsophisticated. The phenomena of dis.
ease are adduced to explain the actions of
health ; the chemical changes which dead and
common matter undergo, are often assumed to
account for the causes and phenomena of life.
To the late MR. J. HUNTER, to DR. GOODWIN,
SPALLANZANI, and a few others, we are
eminently indebted for many valuable facts obtained
through the medium of experiments per4
PRINCIPLES OF SCIENCE.
formed on living animals : these facts acquire
their intrinsic worth, from their exposing to our
view, internal operations which were before
concealed; thereby manifesting the natural
condition of things without altering it.
Cruel and horrible as these experiments were,
if they cannot be justified, it is hoped that they
will find considerable palliation, in the motive
which led to the execution of them ; the earnest
hope which a few of these gentlemen entertained,
of bringing light out of darkness, and
that the sufferings of the brute might ultimately
prove beneficial to man. Although humanity
feels a pang at the recollection of such pursuits,
they ought nevertheless to be tolerated to
a certain degree, when performed by those who,
having an end in view, are anxious to prove, by
the fact of experiment, the truth or error of the
principles of physiological science, entertained
by them.
For that numerous class of pretenders to physiology,
for those minnows in science, who
without end or design, are impelled, by blind
chance and mere curiosity, to inflict the most
barbarous cruelties on cold and warm blooded
animals, there is no excuse ; any more than for
those, who mutilate and extirpate different organs
from the living system, in order to ascertain
the natural functions which those organs
are intended to perform, and the use which
PRINCIPLES Otf SCIENCE.
they are designed to subserve. The merit of
many of these gentlemen, in other points, is not
meant to be depreciated ; it is in many respects
entitled to praise. When some of them, however,
arrogate to themselves the claim of furnishing
to the world all the physiological knowledge
in it, and, as if alone qualified to discuss a
physiological question, receive with slight, and
consider as mere drivellers those who take
natural rather than artificial phenomena, and
whom they contemptuously denominate closet
philosophers, we cannot but feel amused with
the folly of such conceits.
In order to appreciate the whole merit to
which they are entitled, it ought to be examined
; and I am persuaded it will be found that
the reason of this conceit and pride arises in
consequence of mistaking art for science, the
man who carries the hod, for the architect who
designs, and, from confounding the laborer
and bellows-blower with the physiologist and
metaphysician.* I do not include the mail
* It is not to be supposed, that I am singular in this opinion
; it is the opinion of some of our best experimentalists
also. I shall quote a passage from Dr. Enfield, the learned
Professor of Natural Philosophy at the establishment or university
of Warrington ; it is contained in the preface of his
celebrated work, intitled the Institutes of Natural Philosophy;
and dedicated to Dr. PRIESTLEY. After recommending
a knowledge of mathematics, he observes, that,
” a mechanic
6 PRINCIPLES OF SCIENCE.
who from a superiority of intellect, possessing
a knowledge of cause, foresees and foreknows
the effects which will inevitably follow, and is
anxious to put his science to the test, and to
prove its truth by experiment : a philosopher,
such as this, is seldem qualified for the task of
performing it, he rather delegates the execution
of it to others, than performs it himself. What
qualifications, I would ask, are requisite for the
experimentalist in chemistry ? There is not, I
am persuaded, an experienced artist in any of
our manufactories, who is not able to mix the
different ingredients intended to be employed,
who would set about making a machine without the requisite
tools, would not act more absurdly, than a student who would
attempt to understand the science of natural philosophy, without
those helps. A preceptor, who professes to teach this
science in the easy and amusing method of experiment alone,
is an architect without his rule, plumb-line, and compasses.
Facts are, it is true, the materials of science; and much praise
is unquestionably due to those, who have increased the public
store by new experiments accurately made, and faithfully
related. But it is not in the mere knowledge, nor even in the
discovery of facts, that philosophy consists. One, who proceeds
thus far, is an experimentalist ; but he alone, who by
examining the nature, and observing the relation of facts, arrives
at general truths, is a philosopher : a moderate share of
industry may suffice for the former ; patient attention, deep
reflection, and acute penetration, are necessary for the latter.
It is therefore no wonder that amongst many experimentaUstt,
there should be few philosophers
”
PRINCIPLES OF SCIENCE. 7
to blow the bellows, and even to decide on
the result that ensues, as well as the best
chemist that has ever existed.
The same limited means are alone wanting in
physiology. There is not a lad of twenty years
of age, who comes from the country to any of
our hospitals in town, and who, after passing
with common industry two seasons in any of
our anatomical schools, is not perfectly competent
to perform any physiological experiment.
In addition to a precise knowledge of
position, the only requisites wanting, are a
steady hand, a sharp knife, a tolerably good
pair of eyes, and an unfeeling heart.
To rip open the flanks of a dog, as well as of
a calf, to drag any particular organ out of its
situation, to paw and to squeeze it, to decide
whether it swells or contracts, whether it causes
pressure or not, on surrounding parts ; to tie a
ligature upon the vessels or tubes, with which
any organ is supplied; or, to extirpate the
organ altogether, and finally cut the animal’s
throat, and strip the skin for the sake of the
leather, can be performed, as perfectly, by any
carcase-butcher in any slaughter house, as by
the generality of physiologists.*
* To free myself from the charge of exaggeration, and to
enable the reader to decide for himself, how far I am justified
in saying that the degrees of talent necessary to perform an
8 PRINCIPLES OF SCIENCE.
Men, such as these, however qualified they
may be to act well, seldom think correctly.
experiment are very trifling, and that it it generally done with
a degree of cold-blooded apathy which is shocking to humanity,
I shall relate a few, among a multitude of similar experiments,
that were made on living dogs, in order to ascertain
the change of color which the blood underwent, during the
process of respiration.
” I procured several large dogs,” says
one of these gentlemen,
” and after removing the sternum or
breast bone of each, and exposing to view the trunks of the
pulmonary arteries and veins, &c. &c.” But another, and he,
by far the most eminent of all, after going through the preliminary
operation of cutting the parietes of the thorax, and
sawing the ribs, and exposing to view the organs which it contains,
says,
” I have repeated this experiment several times
upon several animals, and commonly for half an hour at a
time ; which was sufficient to allow me to make my observations
with coolness and accuracy ; it was curious to see in the
first part of the experiment, the coronary arteries turn darker
and darker ; but on blowing air into the lungs, the blood gradually
resumed the florid red. 1 cut and sliced off a piece
from the lungs, and found that the colour of the blood which
came from the wound, corresponded with the above effect,”
&c. &c.
I should not have dwelt upon this subject, had I not known
that the practice of torturing animals among young men is
become, of late, very much the fashion. Such are the tender
mercies which they have for themselves, that to take away
from the poor creatures the only consolation left them, the
power of expressing, by their cries, the anguish which they
suffer ; they first begin by cutting and dividing the recurrent
branch of the parvagum, which subserves to the motion of the
tongue and lower jaw, and, by that means, prevent the animal
from howling.
PRINCIPLES OF SCIENCE. 9
Were we to descend to particulars, it could
easily be proved, that the premises which they
assume, consisting, for the most part, of the
mutilated and unnatural condition of things,
can seldom convey to the mind data, fit for
physiological science ; that the conclusions
which they draw, however true they may be
from the principles which they assume, are
most erroneous in themselves, so far as relates
to the thing which they are intended to explain.
This piece of humanity is exactly analogous to that posessed
by Santerre during the maisacres in Paris, in the early part
of the French revolution. At that time he was commanding
officer of the national guard, and it was in his power, had he
possessed the inclination, to have prevented a multitude of
persons from being sacrificed: during this period, however he
remained quietly at table, while innocent blood flowed in torrents.
One of his satellites, by accident, put his foot on the
tail of a little dog situated under the table, which occasioned
the dog to squeak ; Santerre, in great agony, reproached v, ith
bitterness the inhumanity and cruelty of the fellow who caused
the sufferings of the poor animal. I cannot avoid lamenting,
more especially, that in many of the popular lectures which
are given in different public and private institutions, in this
country, that ladies sit with composure, to see the sciatic
nerves of frogs stripped of the surrounding flesh, and by
means of the Galvanic fire, the animal thrown into the most
dreadful convulsions : to behold different animals poisoned
by means of different mephitic gases ; or, by placing them
under the receiver of an air-pump, and exhausting the air out
of it, to observe, with indifference, the infliction ofa languishing
and lingering dath.
10 PRINCIPLES OF SCIENCE.
The system of induction introduced by Lord
Bacon, had not for its end, as many of his unworthy
followers have supposed, the mere abstract
accumulation of facts. Facts, isolated
and unconnected, resemble the rough materials
intended for the foundation of a magnificent
edifice. The carpenter who chips the timber,
and the mason who polishes the marble, are not
to be considered as the men of science ; but he
alone, who, from a precise knowledge of principles
and of causes, is able to direct those
materials to be arranged with order, form, and
symmetry. It was with that end in view, that
his lordship analysed before he generalised;
that he has separated the individual from the
species; the species from the genus ; and, from
a multitude of effects, endeavoured to arrive at
cause.
Had his lordship limited his views to induction
only, or had he cherished a hope, that
through a multitude of forced and unnatural
effects, he would ever have been able to establish
true principles of science; instead of being
the father of philosophy, as he has been called,
he would have been its greatest enemy.
In the analysis of facts which are intended
to constitute the principles of any science, it is
of the first importance, that none should be admitted
but such as are scientifically efficient of
the conclusion, so that the effect produced,
PRINCIPLES OF SCIENCE. 1 1
shall always correspond to the nature of the
producing cause ; that we should separate
partial from general facts, accidental and transient
attributes from those that are permanent
and essential. It is by a process, such as this,
that we become possessed of those individual
facts which form the base and the source of
every science, the immediate and proximate
cause whence effects are derived : it is by the
enumeration of these attributes, which, always
abiding in the subject to which they belong,
apply universally to every individual of the
species, characterise its nature, and distinguish
it from a body belonging to every other class.
Without the full possession of these permanent
and universal facts, a general, not a particular
knowledge of any subject can ever be obtained :
without history, we can never have definition ;
and without axiom, there can be no science.
It is on principles such as these, of selfevident
truth, that the whole of mathematical
science is founded, as well as every other
branch which deserves the name of science.
Without the possession of these first principles,
it has ever appeared to me impossible, that we
can obtain any science of the phenomena which
are produced ; without them, a general, not a
particular knowledge may be acquired; we
may become historians, but not philosophers ;
good artists, but not men of science. Know12
PRINCIPLES OF SCIENCE.
ledge, properly so called, does not simply consist
in the impressions made on the senses by
the operations of external phenomena ; true
knowledge can only be admitted to exist, when
we are in full possession of the cause whence
the effects are derived ; and he alone can be
denominated the man of science, who is able to
connect the cause with the effect.
These principles are not only more powerful
and true than the thing produced, but the actual
cause of its production : they possess the
power of imparting their own efficacy and
energy to the bodies on which they operate, and
they constitute the cause whence secondary
effects are made to flow: by which, the principle
of life, for example, resident in the semina of
plants, or in the ova of animals, is enabled to
act on matter dead and common, and to convert
it to a living state ; by which, the sun, as the
principle and fountain of light, becomes the primary
cause of illumination in general; by which,
the expansibility of air is enabled to excite motion
in matter, passive and inert. Many men,
who have not learned the principles of particular
sciences, can frequently assign reasons,
or the cause why, for the effects which they
behold ; they seem, intuitively, to possess a degree
of science, and to attain rules by chance,
which instruction is especially designed to unfold.
Mr. HARRIS, therefore, very accurately
PRINCIPLES OF SCIENCE. 13
observes, that in the investigation of principles,
we are first taught to learn that every science,
as arithmetic, geometry, music, astronomy, &c.
may be resolved into its theorem, every theorem
into its syllogism, every syllogism into its
proposition, and every proposition into certain
simple or single terms.
If we were to begin the discussion of any
branch of science before we had attained a
knowledge of simple terms, which are in themselves
irresolvable, it is evident that we should
begin in the middle ; and, if we were to begin
at the theorem itself, before we had attained
a precise knowledge of a syllogism, and of a
proposition, we should begin not merely at the
middle, but at the very end. Simple terms,
therefore, constitute the base, the punclum
saliens, whence all scientific knowledge ought
to commence ; to begin from other data, not
only leads to hypothesis, but is an inverted
order of learning.
It is by the previous attainment of this simple
knowledge, that we become qualified to
learn the connecting media, of which the most
compound knowledge is formed, and that the
extreme parts, the beginning and the end are
united, so as to compose one whole. It is in
this investigation that the office of science consists
; and forms the true object of its pursuit.
Science, therefore, begins from principles, and
14 PRINCIPLES OF SCIENCE.
proceeds through proper media to the conclusion;
from cause to effect, from things
general and universal, to things particular and
accidental.
This power of the mind to learn, and to be
instructed, is termed, by Mr. Harris, natural
capacity, and is an attribute common to all
men ; the superior facility of being taught,
which some possess above others, is called
genius; the first transition, or advances, from
natural capacity, is called proficiency, and the
end, or completion of proficiency, habit: if
such habit be conversant about matter purely
speculative, it is called science; if it descend
from speculation to practice, it is termed art ;
and, if such practice be conversant in regulating
the passions, it is called moral virtue. Before
the habit of moral virtue can be attained, there
are many appetites to be curbed, various propensities
to be corrected, and many temptations
to be resisted.
Although it is unquestionably true, that
there exist different sciences that may be said
to belong to one and the same genus, in
which the principles of the one may be legitimately
transferred to the other, it is, nevertheless,
very seldom the case. Principles of science
do not emigrate, as migratory birds at
different seasons, to different countries ; individual
sciences, for the most part, have their
PRINCIPLES OF SCIENCE, 5
own facts, and their own principles. The conduct
of those who take false analogies for the
explanation of the same phenomena, or the
principles of dissimilar sciences, to account for
the effects produced in those to which they
have no relation, cannot be too strongly reprobated
and condemned.
If the mere capacity appertaining to different
species of common matter, or even the chemical
power which it may be supposed to possess,
were employed, as it too often is, to account
for the cause of vitality ; if the principles
of hydraulics were employed to account for the
motion of the fluids in the animated system ;
or those of pneumatics for the process of respiration
; in short, if the principles of chemical
science were advanced to prove the nature of
vital action in general, and of ratiocination in
particular ; facts, or principles, such as these,
would unquestionably be false. The same
conclusions may be drawn if the principle of
vitality in plants were adduced to prove the
principle of instinct in brutes ; or the principle
of instinct in brutes employed to ascertain the
nature of intellect in man. These facts having
no reference whatever to the particular subject
which they were intended to demonstrate, and
being, in themselves, inefficient and defective to
prove the conclusion, must ever be considered
as false. The principle of intellect in man can16
PRINCIPLES OF SCIENCE,
not be proved by the nature of brutal instine^,
any more than the vitality of plants can be
proved from the chemical properties of matter,
dead and common: in this case, physiology
and physics, chemistry and metaphysics, would
be confounded together.
The same observations may be matfe, if the
facts which appertain to vision, were employed
to account for the cause of hearing, or of those
which appertain to taste, with those which belong
to the olfactory sense.
ilf we proceed from physiological to mechanical
sciences, the same remarks will be equally
applicable. If the principles of hydraulics
were employed to account for the effects produced
in pneumatics ; and, even if those of
pneumatics were advanced to prove the nature
of optics, such facts would be false ; as false,
as if we were to confound the facts which appertain
to time, with those that belong to place ;
figures with lines, and lines with figures ; and,
attempt to prove magnitude by numbers, or
numbers by magnitude; and confound geometry
and arithmetic together. For the express purpose
of guarding against this great error, it
would seem, that Sir ISAAC NEWTON, in his universal
arithmetic, praises the antients for not
deducing geometrical conclusions from arithmetical
principles, and for not confounding geometry
and arithmetic together.
” Each of these
PRINCIPLES OP SCIENCE. 17
sciences,” says he,
”
possessing principles peculiar
to itself, and distinct from other sciences.”
What other construction can these words bear,
than that he who employs the primary and permanent
facts which constitute the principles, or
the axioms (as I may call them) of every individual
science, in order to account for the
effects produced by the power of the facts, or
principles, belonging to another, between which
there is no analogy whatever takesfalsefads
for his data. False facts may, therefore, be
considered as facts which are assumed for false
principles ; or, false causes, to which effects are
improperly referred : the phrase, by the driveller,
will either be misunderstood, or be considered
as an absurdity ; by the ignorant in
science, as contrary to appearances, but not
an absolute contradiction ; as a paradox, but
not a nonentity;* by the man of real science,
the phrase will be admitted as legitimate and appropriate,
and be, by him, constantly appealed
to, as the true and primary cause of error. He
will ascribe to false facts, the mass of false
* There is an evident difference between a paradox and a
contradiction. Both, indeed, consist of two distinct propositions,
and so far only are they alike ; for, of the two parts
of a contradiction, the one or the other must, necessarily, be
false ; of a paradox, both are often true, and yet when
proved to be true, may continue paradoxical that is, contrary
to general appearance.
C
IB PRINCIPLES OF SCIENCE.
philosophy which continues to prevail at
day. I have, perhaps, dwelt longer on this
subject than was necessary ; I was, however,
led to it in consequence of the complete ignorance
which it appeared to be involved in, by
those who ought, from their situation, to have
been better instructed and informed ; the idea
of false facts was not only decried by them,
but even attempted to be ridiculed.
Having endeavoured to show what true principles
are, and what false principles are not ;
I shall now proceed to point out the errors of
taking false analogies as principles of science,.
Wherever a uniformity of nature and of character
exists between different bodies, analogy
becomes a legitimate source of induction; it is
from the analogy which subsists between the
phenomena of life and health, of disease and
death in plants, that these may often be employed
to illustrate the correspondent changes
which take place in brutes, as well as in the
human species. Analogy becomes also a legitimate
source of induction, when a similarity of
nature exists between bodies whose functions
are the same, however dissimilar they may be
in structure and appearance. By analogy we
predicate the same attributes to thegills of fish,
as we do to the lungs of the mammalia ; to the
ovaries of a sprat or of a whale, as to the ovaries
of a rabbit, or of an elephant. And, it is
PRINCIPLES OF SCIENCE, W
because geometry defines many of the assumptions
and suppositions of the science of optics,
as well as of other sciences, that analogy between
them may often be admitted.
Analogy may be admitted throughout the
various species of common matter which exist,
whose nature and properties are the same, however
different in appearance they may be ; between
the capacity of a lump of clay, and of a
piece of flint; between the flexibility of lead
and of iron ; between the elasticity of steel and
of whalebone ; and between the expansibility
of gases in general, however different in other
attributes. The reason why analogy between
these different genera is admissible is, that
however different from each other their particular,
or secondary properties may be, they,
nevertheless, always continue to retain the
same generic character; that, although the
chemical characters of particular gases are
proved to be totally different from others, all
however are expansible. The same may be
said of elastic, and of flexible bodies.
To bodies such as these, Sir ISAAC NEWTON’S
second rule of philosophising may apply, that
” of natural effects of the same kind, the same
causes are to be assigned.” It must, however,
be very obvious, that this rule can never apply
to bodies whose nature and properties are
essentially different from each other, and bec2
20 PRINCIPLES OF SCIENCE.
tween which no analogy whatever exists. It is
not legitimate to make use of analogy between?
flexible and elastic, any more than between
elastic and expansible bodies ; much less between
matter which is ponderable and dark,
and such as is imponderable and luminous ;
between that which is passive and opake, and
that which is essentially active and transparent ;
between a cloud of dust, and the rays of light ;
between the natural obscurity of this globe of
earth, and the illumination and splendor of the
sun.
In order, therefore, to prosecute to a successful
termination, any branch of science, it is
of the utmost importance, that we should be in
full possession of the first principles, on which
that science depends ; subsisting as causes
from whence the effects proceed ; and that the
definitions we employ, should be determinate
and precise, expressive of the thing signified.
This previous and antecedent knowledge, not
only comprehends a knowledge of the nature of
the subject itself, and of the terms by which its
existence is known and understood, but also
the various attributes belonging to it; the
nature of which will form the subject of the next
chapter.
ON THE ESSENTIAL PROPERTIES OF MATTER
WITH RELATION TO VITALITY.
THE attributes which different bodies possess,
may be divided into two classes ; into those
that are inherent, or essential, and into those
that are accidental and derived; into such as
are resident within the body originally, and are
inseparable from it ; and into such as are produced
by the action of external influence upon
- When a body acts independently of external
influence, the action produced constitutes the
true test, by which a knowledge of its nature,
is to be obtained : on the contrary, when a body
acquires properties by the agency of an external
cause, the creation of those properties, may be
considered as constituting the vast tribe of
accidents in bodies, as they have been called by
some, and of secondary qualities by others, and
which are obvious and perceptible to our senses.
22 PROPERTIES OF MATTER
If the nature of each be considered, the
will be found very different from the other ; it
is not by the transient and accidental color of
the skin, which different beings possess, whether
that color be pallid or red, that the human
species, in general, is characterised. The external
color may be imitated by art, upon -a
lump of clay, or a block of wood ; upon a dead,
almost as perfectly, as on a living subject;
these qualities, therefore, may be considered as
secondary, or accidental. It is, on the contrary,
to the more permanent and indelible
attribute of organisation, and of form of
action and of power, that animated beings
essentially possess, that every individual is
known to be what it really is, awd through
which it is distinguished from every thing else.
The same observations equally apply with
respect to the different species of common matter,
of which the world is composed ; although
each species possesses particular properties of its
own, which are different from others, and that
a variety of changes between them are perpetually
taking place : the most solid bodies are
cften liquified into a fluid, and subtilised into
vapor, that vapors are often condensed, or
consolidated into a liquid, and even a solid
form. In whatever form it may exist, every
particle of which it is composed, continues to
possess one attribute which is common to the
WITH RELATION TO VITALITY. 23
whole, and which is inseparable from it the
attribute of extension extension into lengthbreadth,
and thickness.
If we proceed frora this attribute universal,
to detail the attributes particular, which different
bodies obviously possess, we shall find
them to be totally different from each other ;
and that a great diversity of changes is constantly
taking place between them. To ascertain
the nature of these attributes, and the
relation which they bear to each other ; finally,
to trace the phenomena, 0r effects which are
produced, to their producing cause, constitute
the especial objects which physical science is
designed to explore, and the true pursuit of a
natural philosopher.
Among the first advances that were made
for the purpose of putting confusion into order,
<Jassifications of their various orders were formed
; the infinite multitude of individuals which
exist, were arranged under particular species ;
different species under particular genera ; to
which each individual could be easily referred,
according to its general character and mode of
subsistence.
It was with a view to this end, that the whole
of the material world has been commonly
classed, under three different orders, or kingdoms
; into animal, vegetable, and mineral. A
generalisation, such as this, appears tomehighly
24 PROPERTIES OF MATTER
objectionable, because extremely defective.
Instead of comprehending the whole, it excludes
a part, it excludes that immense and
indefinite portion of matter, which, instead of
being mined and immured within the bowels of
the earth, subsists, for the most part, out of it ;
it not only excludes water, and gaseous bodies
in general, but the whole planetary system in
particular. To supply this state of imperfection,
I shall class the whole system of nature,
as it has been called, and the matter of which
it is composed, under the three distinct heads,
of common, of living, and of dead matter.
FIRST, By living matter, I comprehend the
various orders of living beings with which the
universe is replenished and adorned.
SECONDLY, By dead matter, I confine myself
to the exuviae of animals, and of vegetables ; as
well as to the whole substance of which these
beings are composed, after the actions of life
are at an end, and the state which is known by
the appellation of death.
THIRDLY, By common matter, I mean the primitive,
or original materials, or elements, of
which the world is composed ; matter which
either, has never received the participation of
life, or having received, has lost it, and been resolved
back into a common state.
To physiology, belongs the province of investigating
the properties of living matter. To
WITH RELATION TO VITALITY. 25
physics, such as is dead, or common. Correspondent
to the difference of character which
subsists in matter dead, or common, whether
solid, liquid, or gaseous, a subdivision in the
science of physics is made. Geology refers to
the solid and’ common matter of which the
world is composed. Hydrology to liquid, and
meteorology, to that which subsists in a gaseous,
or aeriform state ; and finally, chemistry is designed
to examine, and to ascertain, the more
intimate and particular qualities, which each
substance possesses, and the changes it undergoes
by union and combination ; the means
employed are those of analysis and synthesis.
If we begin by examining the attributes of
common matter, in its form the most simple
and uncombined, we shall find that an increase
of bulk alone ensues, by the aggregation of its
parts ; and that if a union takes place between
bodies, whose qualities are different, both lose
by the combination some of the properties possessed,
separately, by each ; whether it be a
solid, or a fluid ; an alkali, or an acid ; a
metallic ore, or a gaseous fluid. If matter is
acted upon by some external agent, and motion
is produced ; the motion produced perpetually
diminishes, and is ultimately lost : the matter
impelled, gradually verges from the state of
activity into which it had ben excited, and
returns to the one in which it existed before,
#6 PROPERTIES OF MATTER
passive and inert. Whether, therefore, we con*
template the nature of common matter, at rest,
W in motion ; at unity, or in union ; whether
the changes it undergoes proceed from motion
mechanical, from mixture chemical, or from
both together, we shall find it a universal truth,
that the same effects, universally result froia
Jhe operation of the same causes.*
Ifwe extend our views to animated beings in
general, we shall find that the faculties and
powers so varied and wonderful which they
severally possess, prove that each system, not
only in the progress of its evolution, but in the
actions it performs, is governed and impelled
by laws, distinct and peculiar dependent on
the class to which it belongs ; and that the
matter itseJf, of which it is composed, is, in it$
attributes, totally different from common matter
in a passive state. In common matter, an increase
of bulk is invariably produced, in proportion
to the quantity of matter applied.^
* It has been owing to the uniformity in the effects which
common matter is found to describe, that rules have been
formed to which those effects correspond. These rules, by
some, are called Principles, by others, Laws. The rules of
Mechanics, illustrate and explain the operation of matter in
point of quantity ; of chemistry, in point of quality ; of geometry,
the quantity and degree of motion described.
t I allude, of course, to homogeneous matter only ; chemical
union often causes a condensation between the parts,
and a consequent diminution of volume.
WITH RELATION TO VITALITY. 27
In a living system, no addition of matter can
produce an increase, after it has attained the
full perfection of its evolution. The increase
of bulk in common matter, is derive^ by accretion
from without. In the living system, it
proceeds by a power of conversion, and of secretion
from within. In the one, the whole collected
mass is irregularly heaped up, rudis indigestaque
moles : in the other, the most exquisite
symmetry and order mark the arrangement and
disposition ofall its parts. Theformer is destitute
of all power of fabrication and restoration ; the
latter is endowed with both ; while common
matter, by its inertness, continues permanently
the same through the long course of revolving
years ; the latter, is in a state of perpetual mutation
and action ; and, after having attained its
period of perfection, perpetually verges to inevitable
decay.
If we proceed to examine the motions which
are excited in an inanimate machine, however
simple or complicated the construction of the
machinery may be, and compare them with the
mechanical actions that flow from the power of
a living system, the same contrariety will be
found to subsist. In a hydraulic machine, the
water is impelled by a vis a tergo alone from
without :; In a living system, the fluids are propelled
by a power from within, inherent in the
vessel by which the fluids are contained. In
28 PROPERTIES OF MATTER
the one, a Remora is caused by the friction of
the water upon the containing vessel ; in the
other, the power of the containing vessel is the
cause of the velocity in the fluids they convey.
In the former, the distribution is regular and
uniform ; in the latter, we constantly behold it
altogether different ; being often increased, or
diminished, throughout the same parts, at different
times. A mere blush in the face decidedly
proves, that, although vessels the most
extreme and minute, possess a power common
and concurrent with the vascular system at
large, they are, nevertheless, endowed with
an exclusive one also. In the former, the
water remains unaltered and unchanged ; in
the latter, the blood suffers a constant alteration
in its nature.
If the effects of the fluids upon the vessels of
both be examined, we shall find them to be, in
each, totally different; the effect which is
caused by the pressure of fluids upon solids,
and of solids and fluids upon each other, however
small that pressure may be, is invariably
attended with mechanical destruction, and loss
of substance.* In the one, the degree of mechanical
destruction altogether depends on the
quantity of pressure applied, and of motion pro-
* In the living system, instead of a waste being produced,
an increase of substance generally ensues.
WITH RELATION TO VITALITY. 2S
duced ; in the other, the natural actions of the
living system contribute to the acquisition of
strength. Great and striking as appear to me
the marks of difference by which systems, common
and living, are characterised, all comparison
is lost, when we reflect on the imbecility
and passivity of the one ; on the irritability and
mobility, (both voluntary, involuntary, and
mixed of the other,) with the power of abstraction,
and of ratiocination of some ; of reproduction
and restoration of all. If the food be
examined which subserves to supply the wants,
and to restore the wastes which every living
system undergoes, it will be found in its attributes
to be totally different from what it
was before. The commutation which the
food has undergone, after the process of digestion
has been accomplished, is total and
complete. Gases are bereaved of their expansibility,
adds of their acidity, alkalies of their
acrimony ; all of the order of their affinities,
and rendered bland and mild : by them, solids
are liquified, liquids gelatinised and made solid;
things simple become compounded; such as are
inanimate are animated ; animated things are
killed and revivified ; the most sapid bodies are
rendered insipid; the most putrid matter is deprived
of its putridity, and made antiseptic and
fresh; the most fresh and antiseptic is rendered
susceptible of undergoing the processes of pu3$
PROPERTIES OP MATTERT
trefaction and fermentation- Language itself
is insufficient to describe the difference which
exists between the laws, by which, animated
beings are governed, and those, to which matter,
either dead or common, is amenable.
While the phenomena which common matter
displays are regular and definite, and uniformly
and invariably the same ; we behold, on the
contrary, the same kind of matter applied to
different living systems, as well as to the same
Systems at different times, changed into a nature
totally different : we behold, in the same
field, and in the same soil, a multitude of different
vegetables fed and nourished by water
and by air, in quality precisely the same, and
yet assuming an organisation and form totally
different,
It is well observed by Mr. MASON GOOD,
(whose learning and research I am happy to
acknowledge,) that the most burning sands of
hot climates, even the karo fields of the Cape
of Good Hope, (so sere and adust that no water
can be extracted from them,) are the media
in which the most succulent vegetables of
Which we have any knowledge flourish and
evolve ; so deleterious, indeed, is a wet season
to their growth, that they are destroyed by it.
There are also various tribes of vegetables that
are destitute of radicles, and which can only
be supported and nourished by the air, and by
WITH RELATION TO VITALITY, 31
ihe moisture which the atmosphere contains ;
a large portion of tire class of fuci has no root
whatever. It is also stated that the aerial
epidendron, the epidendron flos aeris, (denominated
aerial from its’ extraordinary properties,)
a native of Java in the East Indies, on account
of the elegance of its leaves, the beauty of its
flower, and the exquisite odor which it diffuses,
is plucked up by the inhabitants, and
suspended by a silken cord from the ceiling
of their apartments, from whence it continues
from year to year, to put forth new leaves,
to display new blossoms, and exhale new
fragrance,-^-although fed out of the simple
bodies I have before stated.*
This assimilating and convertible power over
different kinds of food in the digestive organs,
is equally proved by animals, whether herbivorous,
carnivorous, or omnivorous. Meat cut
out of the same joint, bread from the same loaf,
water drawn from the same fountain, and portions
of air separated from the same volume,
given to a man or a monkey, to a dog or a cat,
will lose every vestige of its former qualities,
and be converted to the particular nature of the
system- to which it had been applied.
* See Mr. GOOD’S Oration before the London Physical
Society.
32 PROPERTIES OF MATTER
This power of decomposing the most minute
particles of matter, which the assimilating organs
possess, and of converting it to the nature
of the system to which it has been applied ;
although obvious to the most simple observation
of the most common observer, has been
further ascertained by experiments. Mr. ABERNETHY
procured a rabbit, six weeks old, and
fed him with’a quantity of young cabbage and
lettuce which had grown on flannel, sprinkled
with distilled water; the animal, it was found,
preserved his health, as perfectly, as if he had
been placed in a warren.
Dr. FORDYCE enclosed in glasses, filled with
common water, several gold and silver fish ; at
first, he changed the water every twenty-four
hours, and afterwards, every three days; on
this food alone, the fish continued to live and
to grow for fifteen months. As Dr. FORDYCE
suspected that it was possible, animalcules
might have previously existed in this water, he
exchanged the well for distilled water : after
adding air to it, to prevent the possibility of
insects getting access within the vessel, he carefully
closed it up : the fish, however, grew and
performed all their natural functions as perfectly,
as if they had been swimming in a reservoir.
The fact is equally proved by those animals
who live principally upon carrion, upon rotten
cheese, and the exuviae both of animals, and
RELATION TO VITALITY. 33
Of vegetables ; although corruption is not the
cause ofanimation, animation often flourishes,
with the greatest vigor, on the materials which
corruption has produced.
We should find it generally the case, were
we to take a cursory review of the different
kinds of food, which, different classes of men
take for their nourishment ; however different
the materials may be on which they feed, the
blood and the flesh ofwhich they are composed,
possess the same properties, and yield, by
chemical analysis, the same product ; whether
of a Bramin who lives on vegetables alone, or
of a Tartar who is carnivorous. I would appeal
to the testimony of any determined venisoneater,
whether he has not frequently enjoyed
the green fat of a stinking haunch, without retaining,
in his own person, any of its offensive
flavor. This converting power of the assimilating
organ on putrid matter, was proved by
Mr. HUNTER, and SPALLANZANI. They thrust
pieces of the most putrid flesh, tied by a string,
into the stomach of different dogs, and after
leaving it for some time, by means of the string,
they withdrew the meat from the stomach ;
and, ‘on examining it, they found, that instead
of being putrid and offensive, as at first, that it
had become fresh and sweet.
That all the effects which I have above enumerated,
are accomplished by the activity and
P
34 PROPERTIES OF MATTER
power of the gastric juice, which is secreted
from the surface of the stomach, is admitted by
physiologists in general ; a great diversity of
opinion, however, exists in respect to the mode
of its operation; by a few, very few indeed, it
is concluded, that it is performed by a living
power, resident in this fluid ; by the generality
of others, that it is the consequence of a che-i
mical, not a living, power. If it be by a chemical
power, we ought, by analogy, to expect
that its chemical properties, by analysis, would
be detected ; that it ought to possess some
sensible properties ; that it is either acid, or
alkalescent ; so far, however, from possessing
sensible, or chemical, properties adequate to
account for the extraordinary power which it
possesses, –it appears, upon a close examination,
to be a mere mucous fluid, inodorous and
insipid, neither acid nor alkalescent, neither
turning vegetable blues to a green, or to a
red color: and, by chemical analysis, it
yields neither saline, nor mineral substances.
It is, therefore, I contend, impossible to refer
the action of the gastric juice to any chemical
power which it is pretended to possess ; but,
that it is far more reasonable to conclude that its
activity is, altogether, derived from the energy
of the living power which is supfradded to it,
whose edge is sharper than that of the keenest
knife, whose solvent property is more active
RELATION TO VITALITY. 35
than that of the most eroding caustic. Such,
indeed, is the activity of this living juice, that,
although it remains, during life, in harmony
with the organ by which it has been produced,
its own power, notwithstanding, extends and
continues after the death of the organ itself has
taken place; hence it is, that the stomach has
then been found corroded and destroyed, more
especially in its pyloric extremity, and after
making its way on surrounding parts, these
have been found torn asunder and finally dissolved.
This solvent power was abundantly proved
by REAUMUR, by Dr. STEVENS, and others;
they introduced different kinds of food in balls,
some of which were perforated, and others
which were impervious : the food placed in the
former, to which the gastric juice could have
access, was very easily digested, while the food
contained in the latter remained unaltered.
When we contrast the uniformity of effect
which ensues from chemical combination, with
the variety which results from the assimilating
power of the digestive organs ; we must,
necessarily, be led to conclude, that the effect
produced does not proceed from a chemical
cause. If it arose from a chemical cause, the
change which the food sustained, by the mutual
action between its parts, -would be regular and
uniform ; and the result, instead of being always
D 2
36 PROPERTIES OF MATTER
alike would be generally different. It would
constantly vary, in its properties, according to
the specific nature of the substances, out of
which it was made. The change itself would
be constant and definite, and not liable to the
remission and variation which we witness during
the process of digestion. It is, therefore,
legitimate to conclude, that the process of digestion,
by means of which different kinds of
food are assimilated to one and the same species,
is not a chemical, but a living, act ; and
that the efficient cause of this commutation
does not arise from any active or chemical property,
which in the food inheres, but, that it
proceeds from the power of the organ alone, in
which it is received, and by whose energy, the
, new arrangements of the parts are formed.
It is this unifying power, which the assimilating
organs possess over materials discordant
and heterogeneous ; by which the act of digestion
especially differs from aggregation simply,
or the more complicated phenomena arising
from chemical union and combination. This
assimilating power pervades throughout the
whole range of animated existence. It is, in
essence, the same in animals, *as it is in vegetables
; however diversified the construction of
the organs may be, by which the effect is produced.
In all these, the organs are designed
to reduce different substances to one kind, that
WITH RELATION TO VITALITY. 37
this one substance may be in harmony with the
system at large, and fitted to be acted upon by
the particular power of the different organs,
into various forms. When the assimilating organs,
therefore, perform their functions with
force and with efficacy, they possess the power
of changing and of destroying the sensible and
chemical qualities of the substance they receive;
they not only possess the power to act, but to
resist action ; to change things external to
themselves, without being changed by external
things ; to cotivert them, instead of being converted
by them.
The matter, therefore, which every living
system receives for its nourishment and support,
can only arise out of its aptitude, and its
aptitude proceed from its imbecility and weakness
; from its state of disorganisation and
deprivation, total and complete. It is while it
subsists in this weak and destitute condition,
with relation to the power of a living system,
that, I say, matter is a mere tabula rasa, in all
its parts a chaos of power and of intelligencies
altogether void ; as imbecil and inert, as the
shoe without the foot, or, as the musical instrument
without the art or power of the musician.
It bears the same relation of weakness to the
power of the organ, as the uncolored paper on
which I write, does to the letter I am now
writing ; or, as the block does to the statue.
38 PROPRTI$S OF MATTER
If the block were already chiselled into a statue,
the prior existence of that statue would render
the marble, while in that figured condition, unfit
for the art of the statuary ; tut, being a
plane surface alone, it becomes a fit recipient
for the figures, which the artist intends to engrave.
That this is the relation which actually
subsists, of power and of weakness, between
the receiver and the thing received between
the organs and the food is proved by examining
the converse of the proposition. If the
food, which every living system receives for its
nourishment and support, acted by virtue of its
chemical, or its sensible qualities ; whether of
aggregation or configuration whether of color
or of flavor ; these qualities would constantly
resist the power of the organs, a.nd would
oppose the change, which the matter, by them,
was designed to undergo. Instead of vegetable
and animal matter being converted into chyle,
fermentation and putrefaction would invariably
take place ; if solid substances had been taken
in, for food, those substances would obey the
order of their affinities in the system itself, as
they are prone to do, out of it; a chemica.1
union between the parts would take place and
compound salts be formed. Finally, if they
retained any active or corrosive power, they
would enter into a union with the organ itself,
a caustic eflfect would be produced, and a conWITH
RELATION TO VITALITY. 39
sequent decomposition of it would ensue ; or,
if the matter received, acted by virtue of its configuration,
it would irritate and destroy ; laesion
#nd destruction would be the consequence.*
* The mechanical action of foreign bodies, on the organs
of which the ystem is composed, was particularly manifested
in the man who had swallowed a number of knives. The
circumstances of his case are so singular and extraordinary,
that had I not myself seen the knives, and been perfectly
acquainted with all the circumstances of the case, from Dr.
BABINGTON and Dr. CURRY, two eminent physicians who
attended him while he was a patient in Guy’s Hospital, 1
should feel some difficulty in giving credit to it. The circumstances
were narrated in a manuscript, in the form of a small
book, which was found in the pocket of the man, after his
death j and, as the particulars stated in it, corresponded with
the symptoms of his disease, and especially with the appearances
on dissection, after death, there is every reason to suppose
that the whole is correct. He stated his name to be J.
CUMMINGS, aged 32 years, by occupation a sailor; that, being
at Havre de Grace, he went, accompanied by some of his
ship mates, to a fair held in the afternoon of a Sunday. At
this fair he saw a company of strolling players performing a
variety of tricks ; an account of which he detailed. On their
return, to the sailors on board, among the most remarkable
of the buffooneries which they had witnessed, (with the exception
of Cummings) none appeared so extraordinary, as that of
the man who apparently swallowed a number of knives. Cummings
offered to do the same thing. Being urged by his companions,
he not only actually swallowed his own knife, bat
four other knives, which belonged to the other men. The
knives were all clasp-knives with horn handles, such as are
commonly used by seamen. In the course of three days, he
40 PROPERTIES OF MATTER
If it possessed any permanent power of solidity
or of fluidity the one could not, by the orvoided
them all. Six years after, being at Boston in America,
his fame for swallowing knives having spread, he was induced
one night, to swallow six, and the next day, while in a state
of inebriation, to swallow eight more ; and after very violent
efforts in his stomach and bowels, the whole of them were
voided. Soon after he arrived in this country, and while at
Portsmouth, in December 1 805, he got drunk, and swallowed
Jive knives, and on the sixth, nine more. The persons present,
asserted that he had swallowed four others ; but of this
he was not conscious. It appears, therefore, that in the
whole, he had swallowed at different periods, THIRTY-SIX
knives. The disease which these extraneous bodies produced,
can be better conceived than described. Sufferings, the most
acute, ended in a death, the most wretched. On opening his
body, there were found in his stomach, a large coat button,
with an anchor engraven on it, two silver ornaments, the
back of a silver knife, supposed to have belonged to a lady’s
fruit-knife, and thirteen blades, belonging to some of the
larger knives which he had swallowed. They were tolerably
perfect, as to figure, although much corroded ; so much so,
that the blades were reduced to very thin plates ; beside
which, there were a great number of smaller pieces, which,
apparently, had been separated from the blades. A large
piece of the back-spring of a knife, about four inches in
length, and very sharp at one end, was found passing through
the coloa into the abdomen: five others, in different parts of
the larger intestines, the coats of which they had pierced and
lacerated, and remained suspended in them, in different directions.
As this unhappy man, at the time of his death, was
under the immediate care of Dr. CURRY, of GUY’S HOSPITAL,
it is to be hoped, that he will publish a detail of all the
particulars, more especially* as he is so eminently qualified to
do justice to the case.
WITH RELATION TO VITALITY. 41
gans, be rendered fluid, any more than the other
could be rendered gelatinous or solid and, in
neither case, could it ultimately be fashioned or
formed into the different and varied parts, for
which it was especially designed.
The same reasoning equally applies to its
attributes of color and of flavor. If any particular
color in the food, permanently inhered,
that color would be constantly retained ; by
being retained, it would be always imparted to
the blood, and the complexion, instead of being
different in the individual of every species,
would be invariably the same. This is proved
when substances are introduced for food, whose
sensible properties cannot be altogether obliterated.
Hence it is, that madder imparts a red,
turmeric, a yellow, color to the system at large.
No proof, indeed, is more strong, of the disorganisation
total and complete, which the most
minute particles of matter, in general, undergo
by the process of digestion, than the loss of
flavor and of color which they suffer; the
most odorous and sapid, are rendered inodorous
and tasteless, the most colored, (as far as
it is possible) colorless, retaining no quality
whatever, bulk alone excepted.
It is by the energy of this same living power,
resident in the seed of plants, and in the fecundated
ova of animals, that the acorn becomes
evolved into an oak, the infant foliage expand4?
PROPERTIES OF MATTER
ed into leaves, and the whole process of nutrition
and of growth earned on. It is this power
which constitutes the architect and the fabricator,
by which the whole machine is erected ;
it is the base on which the whole stands, it
forms the bond of its elementary parts, the
cement that unites them into one whole ; it is
the cause primary and efficient, whence the
individuality of every living system arises, in
which the form and the sex it assumes, essentially
reside ; by which, the human species
differs from the brute, the brute from the vegetable,
the vegetable itself from matter inanimate
and common ; this power it is, which I
call life. The matter, which this power has
assimilated and organised, it is, which I call
living matter. It is this principle, which has
been named by ARISTOTLE, sifa$, by HARRIS,
form by STAHL, vis medicatrix naturte by
HALLER, vis vitce by BLUMEN BACH, nisusformativus
by J. BROWN, excitability (if the term
has in it any meaning), and by HUNTER, principle
of life. This last term appears to me so
appropriate and distinct, that I shall consequently
retain it. The principle of life may be
defined to be” thatpower, by whose energy different
species of matter are assimilated to one kind,
a living system organised and formed ; and the
various parts ofivhichit is composed, are protected
and preserved from decomposition and decay”
WITH SELATIO^ TO VITALITY
various organised systems, therefore,
which we behold around us, are nothing more
than effects, produced from efficient and producing
causes ; they constitute the obvious
.and manifest images, of which these primary
principles and causes are the prototypes. It is
very true, th$l these prototypes, or principles,
can only be known through the medium of their
effects ; that through the phenomena of life, we
can know any thing of vitality ; through sensation
of sensibility; through consciousness
of intellect ; through the works of creation,
that we can conceive a knowledge of the Creator
; or, as St. PAXIL eloquently describes it,
”
by which the invisible things of God from the
creation of the world are clearly seen, being
understood by the things that are wade ; even his
eternal power and Godhead.”
The relation of power which those principles,
or causes, bear to the subject, or matter, on
which they operate, is illustrated by every
phenomenon produced by animated beings in
general. It is, for example, by the power of
the artist, over the subject of his art, that he is
enabled to convert and to model it according
to his will ; that the statuary has the power to
chisel the marble into a statue ; the painter to
draw figures upon the canvas ; the carpenter
to cut the timber and shape it,|in the form of a
table, &c. &c.
44 PROPERTIES OF MATTER
It is the DEITY OMNIPOTENT, by whose
infinite power, the universe, in general, is governed
and directed ; who is the first cause, and
the first mover ; so it is the power of life
which constitutes the first cause, and the first
mover of every living system, in particular,
by which it is modelled and formed. Although
this living power is hidden from the
sight of the eye, we may, perhaps, gain a
glimpse of its nature by abstraction, or by the
analogy which subsists between its fabricating
power, and the operation of the mind, when it
employs the organs of the body as its instruments.
When an architect contemplates the
model of a palace, which he intends to erect,
and puts the design on paper, the form of
that palace had a prior existence in his mind ;
and the design on the paper, is nothing else
than the image, or the conception, which previously
existed in the mind of the artist ; the
one is prior, the other posterior, the former is
cause, the other, effect.
In like manner, when a man commits his
thoughts to writing, the letters described on
the paper, are nothing more than the pictures,
or representations of those which previously
existed in the mind; but, as every cause is
better than its effects, mental conceptions must,
necessarily, transcend corporeal operations. In
like manner, life itself, the cause of organisaWITH
RELATION TO VITALITY. 45
tion, must, in its essence, be as superior to the
organisation, as the hand of the artist is more
excellent than the pencil he employs. Organisation
is destined to display the phenomena of
life, as the powers of life unfold and impart
those of organisation ; it is, therefore, legitimate
to conclude, that life is not only a principle,
and a power, higher and prior to the organisation
itself, and a fortiori to the phenomena
that flow from it ; that the corporeal
parts of vegetables, and of animals, in common
with those of men, are nothing more than
instruments, subordinate and subservient to
this principle, by the energy of whose formative
power, one whole system is constituted and
formed ; instead of being formed by the same
means, as machines inanimate and common,
the whole formed and perfected by the addition
of various parts, by a power from without ;
we behold, in every living system, the various,
parts formed by a power from within, from
one united and indivisible whole. It is owing
to the unity and totality of this principle, or
power, that the various parts of the same system
are connected together, by one and the
same bond, why one part of the same system is
not separated, or distinct, from the other, but
that it is all in all, one whole.
It is the specific and individual nature of this
living* principle, or formative power, which
46 PROPERTIES OF MATTS&
stamps the character, and the features ofever?
living system. In its essence, it must be definite,
because the body which it has formed,
dnd in which it is contained, is limited in the
extent of its growth, and is prevented frohi acquiring
indefinite magnitude; although the
causes for its perpetual increase continue to
be applied. It must possess &jortnative power,
because every living system we behold, from
the most gigantic and complicated, to the most
insignificant and simple, is marked by a peculiarity
in the order and arrangement of its
parts.
In its energy, it must be active, not only because
it imparts activity and form to the passivity
and imbecility of matter, but becomes the
primary cause of the various operations which
this living matter performs. In that energy, it
must be temporal, because every living system
is transient and perishable, and in a constant
and unceasing state of progression, perfection,
and decay.
Admitting these undeniable truths, the conclusion
presses itself upon the mind with force
irresistible, that these attributes must, of necessity,
belong to a principle immaterial, and incorporeal,
by whose activity, matter formless
becomes organised ; by whose vivacity it becomes
endowed with the power of action, and
of motion; exerting the same influence, and
WITH RELATION TO VITALITY. 47
governing by the same laws, every particle of
this matter which it has assimilated ; and constituting
the power whence the organisation
originates the fountain, whence health and
disease are made to flow.*
* May we not be permitted to suppose, that the whole
visible world exhibits nothing more than so many passing
pictures, of which these principles are the prototypes, or exemplars;
and, that it is through the participation of them
which matter has acquired, that it may be said to have obtained
a semblance of immortality. May we not be allowed
to credit those speculative men, who, in times of old, have
told us, that it is in these comprehensive and permanent
principles, (or forms, as they have been called,) that the
Deity views at once, without looking abroad, all possible
productions, both present, past, and future ; that this great
and stupendous view is but a view of himself, where all
things lie enveloped in their principles, or exemplars, as being
essential to the fulness of his universal intellection. If
such be the case, the axiom so applicable to the materialist,
Nil est in intellects, quod nonpriusfuit in sensu, that there
subsists nothing in intellect which did not before subsist in
sense, must be reversed, and we ought rather to say, Nil
est in sensu, quod non prius fuit in intellectu, that nothing
exists in sense, which did not pre-exist in intellect.
CHAPTER III
ON THE EVOLUTION OF LIFE, COMPREHENDING
THE END FOR WHICH ANIMATED BEINGS
WERE CREATED.
THE existence of vitality, without organic
action, is proved by the seeds of plants, by the
ova of animals, by the foetus in utero, as well
as by torpid animals in a torpid state : it is
proved by the multitude of cases which we
constantly behold, in the foetal state, in which
many of the organs which are absolutely necessary
to carry on the functions of the adult system,
are altogether wanting. I have seen a
foetus without a head, others with a head, but
without brain; some without lungs, others
without a heart or lungs : many have been
found destitute of abdominal viscera, and with
various other malconformations of the system.
Although these organs were either defective, or
wanting, the other parts of the system were
EVOLUTION- OF LIFE* 49
found perfectly developed, and to have attained
their symmetry and form.
The existence of vitality without organisation,
would more evidently appear, if we
were to examine the state of the living principle
in the seeds of plants and ova of animals.
There are not, in them, any traces whatever to
be found of the future animal, or vegetable ;
there is no foetus in miniature, either of the one
or of the other ; and in animals, (more especially
in those belonging to the higher classes,)
gestation has continued, for a considerable period,
before any bond of continuity between the
different parts can possibly be detected ; neither
is the evolution equal in its progress
throughout the whole ; there are many parts
whose evolution has scarcely commenced, while
the development of others has been completed.
If foetal evolution depended on organic action
in general, a necessity would exist for the presence
of the various substances on which the
different organs are destined to act ; the admission
of air would be necessary to call forth the
action of the lungs ; the introduction of food
into the mouth, would be necessary to call
forth the digestive powers of the stomach.
If the foetus were so situated, its subsistence
would in a great measure depend upon choice,
not necessity ; upon choice without the power
of choosing, upon organic action before organi50
EVOLUTION OF LIFE.
sation had existed ; its condition would be one
of indigency and want, while destitute of tire
means by which its necessities could be supplied
; and the foetal system would resemble the
adult, without the power of arriving at that
state. It is far otherwise ; it appears to me
that the foetal constitutes a medium condition,
forming, on the one hand, a connected part of
the maternal constitution; and, on the other,
separated from it by its own individual existence.
That there subsists an individual existence
in both, separate and distinct from each,
is evident from many facts which we see, in
which the life of the foetus terminates while
that of the mother continues ; and, on the contrary,
in which the foetus survives the death of
the mother. The true end which nature has
in view, during the foetal state, is evidently to
organise those parts which constitute the means
by which the animal is able to provide for its
necessary wants, when the adult state begins :
hence it is, that the organs designed to accomplish
these ends, are especially distinguished
in the foetal state, by the rapidity of their
growth, and the magnitude which they have
attained, when the adult state has begun. I
may enumerate, as thejirst in order, the head,
with the organs of sense, and the nerves which
are connected with them ; secondly, the mouth,
trachea, and lungs ; thirdly, the heart and arteEVOLUTION
OF LIFE. 51
rial system ; the oesophagus and stomach, with
its auxiliary organs; namely, the spleen, the
pancreatic, and hepatic systems; the omenturn,
the intestinal canal, and lacteal vessels,
&c. &c. Under the second head, might be
mentioned, the bones and many of the voluntary
muscles attached to them, the generating
organs, and the venous and lymphatic absorbent
systems, the teeth, the hair, the nails, &c.
During the foetal state, the brain is in a state of
growth without consciousness, and of sense
without sensation ; the muscles are without
voluntary motion ; the lungs without respiration
; the stomach without digestion ; the intestinal
canal without peristaltic motion ; and
the lacteal vessels without absorption.
Although these different organs are in a passive
state, no doubt can exist of their possessing
a power to act, and that they only require
proper objects adapted to the nature of each,
to excite and display that power in the production
of action. It is this power of acting,
of the eye to see, of the ear to hear, of the
tongue to taste, of the stomach to digest,
which I denominate predisposition.
Predisposition, therefore, appears to be a
state of dormant power, or a power in capacity ;
it resembles the elasticity of a spring, while it
is coiled up ; it is like the figures engraven on
a seal, before they are participated by the wax;
52 EVOLUTION OF LIFE.
it is like the gunpowder before it detonates
and explodes ; the gunpowder possesses the
capacity to explode, the seal to impress the
figure, and the spring to react. These attributes,
however, which these different bodies
severally possess, would never be displayed,
unless they were placed under circumstances
fitted for the nature of each ; an unresisting
medium for the spring, a soft body like wax
for the seal, and a particular state of the air
for the gunpowder. It is the same thing with
respect to the living principle, and the different
organs which it has produced ; it not only demands
a certain state and temperature of the
medium in which it is placed, but particular
kinds of food, as well as particular conditions
of it, before that dormant power can become
poiver active, and the phenomena be produced
of organic action. It is in the development of
this power from capacity to energy, from pre^
disposition to action, by which means are employed
with a view to ends, and the final cause
attained for which animated beings were intended.
In proportion as the state of predisposition
departs, the state of energy accedes ; the
difference which subsists between both consists
in this ; in the one case, the organs, have
the power to act without having proper sub*
stances on which to operate ; in the other, the
power which the organs possess, is iro*edi*
EVOLUTION OF LIFE. 53
ately called forth by the application of the particular
substances which they require, and on
which their powers can be properly exerted.
The power, therefore, is resident within ; the
means by which the power is called forth into
energy comesfrom without ; the result of which
is, the production of organic action; the action
produced, is not the cause of life, as has been
falsely and erroneously supposed, but merely
an effect of it. Life, as we have seen before,
may, and does actually subsist without organic
action, although organic action cannot subsist
without the existence Oi* life : life had a prior
subsistence to the organisation, and organisation
itself to the action produced : life is the
primary and efficient cause, of which organisation
is the secondary and instrumental cause,
and organic action itself is thefinal cause. Physical
causes, therefore, may be divided into
two kinds; first, into primary, or efficient
causes, as the great first cause, and the principles
of intellect and of life, which impresses
motion on matter, the passive recipient of a foreign
impulse.* Secondly, into instrumental,
* A final cause, on the contrary, consists in the moral motive
upon the mind, and which can have no influence, but on a
Being that proposes to itself an end, for the action it performs,
chuses means, and thus puts itself in action : although a mechanical
force, and a moral motive are both causes, they derive
iheir energy from most opposite principles.
O4 EVOLUTION OF LIFE.
or secondary causes, which consist in the various
organs of the body, as the instruments
which it employs, in order to assist ; as a telescope
to the eye, a hammer to the hand, &c.
It is with a view to make the end subservient
to the means, of adapting the medium to the
nature of the being which it is to contain, to
produce, in fact, harmony and adaptation be-J
tween both, that the providence of God has
destined particular soils, and particular climates,
for particular classes of beings in which
those ends may be attained. When we behold
the regularity with which the actions of vegetables
are performed, as well as the simplicity in
the construction of their frame,- we are naturally
led to conclude, that those actions, constant
and definite as they seem to be, must flow
from the operation of causes which exist uniformly
and invariably the same, without any
opposing or controling power ; residing within
the system itself, by the energy of which those
actions can either be suppressed, or prevented :
there is not only a progressive development of
particular organs, from the first period of germination,
to the perfection of fructification ;
but an appointed season for the evolution of the
living principle itself, which the seed contains
; the end, of which seems evidently to be
the, propagation of the species, as the means of
affording nourishment and support to beings of a
higher class.
EVOLUTION OF LIFE. 55
The means by which the end is obtained is
not confined to one, but often extends to several
modes, and the offspring produced is perfect
in all its parts ; whether it has been evolved
from a bulb, or from a bud ; from a single leaf,
or from the seed itself. It does not, however,
appear from any knowledge which we possess,
that vegetables have any organs, either of sense,
or of consciousness, with which animals, in
general, are endowed.
When we behold the blossom o”f the sunflower
following the beams of the sun, from
east to west; the dioncsa muscipula seizing flies
by the contraction of its leaves, and making
them prisoners ; the sensitive plant becoming
tremulous and irritable throughout the whole of
its frame, when impressions are made on any of
its parts ; when various other plants have
their corolla opened and expanded, contracted
and closed, at particular periods of the day and
night, as well as under particular states of temperature
in the atmosphere ; I may, perhaps,
be permitted to assert, that these effects are not
the offspring of the living principle alone, but,
on the contrary, that they must proceed from
some small degree of sensitive power which
they may possibly possess, (consequently residing
in a nerve, or something analogous to it,
as the organ alone which is appropriated to
fulfil that office,) resembling the faculty which
56 EVOLUTION OF LIFE.
we see in the oyster, of opening its shell at the
afflux of the tide. This nervous power, how*
ever, if it be one, does not extend throughout
the whole of the vegetable system ; it is principally
confined to the efflorescence, at the particular
time in which it becomes unfolded, and
when it is about to fulfil the final cause of
its existence, in the production of fructification.
Admitting the possibility that something like
a nervous arrangement may exist in a few
species of vegetables ; in those which approximate
the closest, to the first order of the animal
tribe; it does not, however, appear that the
anatomist has detected its existence, or the
physiologist explored its power, in that large
and intermediate class of beings, of fuci and
madrepores, which connect the higher orders of
vegetables, with the lowest of the animal kingdom.
The hydra, or semi-transparent polypus,
when examined in the best light, through the
strongest magnifying microscope, seems to be
nothing more than a granular substance, something
like boiled sago, connected together into
a distinct and organised form by the medium of
a gelatinous substance. In the zoophytes, and
the lowest order of vermes, the whole of their
fabric is nearly of the same simple construction ;
the power of digesting, or assimilating the
^natter of the medium in which they are placed,
EVOLUTION OF LIFE. 57
extends over the surface of their system, similar
to vegetables ; insomuch, that when the
whole is cut into parts, each portion possesses,
within itself, the power of generation and nutrition.
As we ascend in the scale of animals, we are
able to distinguish, between different classes of
each, a considerable degree of difference in the
organisation ofwhich they are composed. Their
digestive organs, instead of being dispersed
over the whole external surface of their frame,
have a particular organ to which this office is
especially allotted ; while vegetables, in general,
act upon the fluid matter by which they
are surrounded, and convert it into nourishment;
animals, in general, on the contrary,
select it by means of the organs of sense, with
which they are supplied. Such, indeed, is the
absolute magnitude of the organs of sense in
these beings, that they can be easily de*
tected : the caterpillar has six eyes on each
side, and in the snail five eyes are distinctly
visible at the extremity of each of its horns,
exclusive of which, a number of fibrils arise
from its mouth, without doubt, imparting to
the sense of taste, an exquisite degree of sensibility.
In the bee, the eyes are not only of a very
large size, but owing to- the peculiarity io their
construction, the area of their surface becomes
3 EVOLUTION OF LIFE.
wonderfully extended ; in shape, they are like
a diamond, having, at least, one hundred sur^
faces, by means of which, they are enabled to
take within their sphere of vision, a great number
of objects.
The optic nerves ofjish far surpass, in magnitude
and power, those of terrestrial animals ;
- MONRO, who has written professedly upon
the subject, says, that the weight of the eye of
a cod, and the depth of its axis, are equal to
those of an ox ; added to which, there is a substance
called tipitum, placed at the bottom of
the eye, which, it is supposed, acts like a mirror,
in reflecting the luminous rays, so as to
enable the other parts of the organ of the eye
to condense them into a focus : by these means,
the concentration of the light to one point, is
so great, that fish can see, and distinguish distinctly,
objects at night. They are destitute of
eyelids, in order that they may be constantly
on their guard, to avoid the attacks of other
predacious animals.
The optic power of serpents, and of birds, in
general, and more especially of the predacious
order, is so well known, as scarcely to require
any detail. The following fact, will, however,
afford some idea of this wonderful power. MR.
BARBER, in the year 1778, being in company
with several gentlemen in Bengal, while on a
shooting party, killed a wild hog, which they
EVOLUTION OF LIFE. 59
left close to their tent, on the surface of the
earth ; in less than one hour after it had been
killed, at the time that the sky was so serene,
that there was not a cloud observable, a small
dark spot, at an immense distance in the air,
attracted their notice ; this spot gradually increased
in size, and they soon found that it
was a vulture, which was flying in a direct line
towards the dead animal, on which it immediately
alighted for the purpose of devouring. In
less than an hour’s time seventy vultures came
from all directions, some horizontally, but the
major part descended from the upper regions,
in which, a few minutes before, no appearance
of them was discernible.
Such, indeed, is the exquisite sensibility of
the eye of birds, that they are provided with a
membrane, (the membrana nictitans,) which
they are enabled to spread over the external
surface of it, so as to protect the retina from
the injuries which it might sustain, on particular
occasions, from the irritation of the solar
rays ; and we all know, that the owl, and other
birds, are unable to bear the light of day, and
that they consequently venture abroad during
the night season only.
The extraordinary faculty which these organs
of sense possess, is manifested under a
multitude of circumstances, which almost challenge
our credibility. Carrier pigeons have
60 EVOLUTION OF LIFE.
been transported to different and remote partfc
of different countries, and, upon being released
from their confinement, have returned, with a
letter round their necks, to the very spot,
whence they had been transported. The olfactory
poivers of dogs of particular species, are
equally certain ; they are enabled to follow
with the greatest rapidity, the game which
they pursue, by the effluvia on the surface ;
and, however, extraordinary it may appear, I
have been assured, that a dog belonging to a
regiment, which it was accompanying, in its
march from Glocestev to Greenwich, and which
had been stolen in the Borough, after making
its escape, returned, two days afterwards, to
the head quarters at Glocester, where it was
received by an officer, who had been left behind.
It is unnecessary for me to go into a
more particular detail of the power which the
organs of sense, in animals, possess ; it would,
however, lead to this general conclusion, that
they are far more active and acute than they
are in the human species.
Without the intervention of these organs of
sese, it is impossible that animals could obtain
any knowledge of external objects ; without
the eye, that they could obtain any knowledge
of color ; without the ear, of sound ;
without the olfactory sense, of flavor ; without
the tongue, of sapid bodies ; and, without the
EVOLUTION OF LIFE. 61
sensitive nerves, of sensation. This sentient
power seems inherent in the nerves which the
organs of sense contain, and these nerves are
the seat in which the proximate cause of sensation
actually abides. The cause of sensation,
does not abide in the external substance,
but in the organ by which the impression is
received. It is owing to this sensitive power,
that we behold animals display fondness and
aversion, action and remission, appetite and
inanition; it is by the energy of these organs,
that animals are able to distinguish,
without experience, in an intuitive manner,
not only the fitness of the medium in which,
by nature, they are destined to reside, but the
substances also, which are best fitted for the
support and nourishment of their frame. It
is owing to this sensitive power, that the dnck
and the chick in ovo, after having pecked open
the shell in which they were enclosed, take different
directions ; the one waddles into the
water, the other hops into the barn ; that the
infant, as soon as it is born, expresses by the
motion of its tongue and lips, its wants and its
appetites, and selects milk, and rejects vinegar
; that we behold in the leech, its fondness
for blood, and aversion to salt.
It is owing to the perfection of this sensitive
power, which these organs of sense contain,
that their energy is strong, and that the gratiti62
EVOLUTION OF LIFE.
cation of the appetite is the object to which all
their actions tend, and the motive by which
they are impelled ; by sense without reason, by
blind impulse, by fatal necessity, by brutal
instinct ; the final cause of which seems to be,
the gratification of the appetite as the MEANS,
and tJie propagation of the species as the END.
With the human species, it is far otherwise.
The inferiority of the organs of sense, in man,
with relation to those belonging to animals, ingeneral,
and the lower order in particular ; as
well as the inferiorty of his faculties of strength
and of motion, of sensation, and of propagation,
evidently prove, that a mere animal existence
is not his true destination. If the end
ofhuman existence depended on the extent and
perfection of living power, man would, in that
case, not only be inferior to the brute, but
the brute itself would be inferior to the vegetable
species : if it depended on the extent
and perfection of the organs of sense, the
condition of the brute would be far superior
to the condition of man, since the organs
of sense in the one, are far more perfect
than they are found to exist in the other.
What man is there whose digestive organs are
equal, in power, to those of animals in general ?
I have seen the stomach of a cod contain a
large haddock, the haddock to .have within
its stomach a whiting, and the whiting a smelt.
EVOLUTION OF LIFE. 63
The shark has been known, at one morsel, to
devour a man, and the large boa snake has
swallowed, without any mastication, animals
of considerable magnitude, not only pigs and
deer, but even a buffalo !
Witk respect to the power in the organs of
sense, the superiority of brutes over the human
species is equally evident. What man is
there, whose eye is equal, in acuteness, to predacious
birds, or to the animals of the feline
race ? whose olfactory organs can bear any comparison
with those in many species of dogs ?
whose muscles are equally strong with those of
the lion or the elephant? An elephant by the
power of its proboscis, will raise, with the greatest
ease, a thirty-two pounder ; and a lion, by
a stroke of his paw, will break the back bone
of a horse, seize, and carry him off between
his jaws, and afterwards devour him for food.
What individual is there whose loco-motive
powers are equal to those of the most sluggish
greyhound ? While our best pedestrians believe
that they have performed feats the most astonishing,
by walking for four or five successive
days, forty or fifty miles, assisted by intervals
of sleep and generous diet different kinds of
fish will traverse, without resting or sleeping,
from one continent to another. It is a well
known fact, that the same shark has followed
the track of the same ship, from the Indian
64 EVOLUTION OF Lilt.
ocean to the English channel, in order to devour
the offal by which it was allured, and
which had been thrown overboard.
If the comparison between vegetables and
animals, and especially the human species, were
made, with respect to the means by which their
wants are supplied, we should be led to admit
the self sufficiency of the one, and the total indigency
of the other. While vegetables flourish
and evolve for months, years, and even centuries,
by means of fluids only, of the” simple
nourishment of water and of air, which they
principally receive through the medium of the
soil, animals require not fluids only, but solids
also. In the one, the conversion of the food
from a common to a living state, is accomplished
by the easiest possible means ; in the other,
the agency of different organs is necessary, before
the process of assimilation can be accomplished.
While theformer flourish and propagate
without the necessity of having organs of
apprehension ; such is the imperfect condition
of the latter in these respects, that without organs
of apprehension, they could riot possibly
obtain the means of support ; they
would perish for want, without fulfilling the
end of their existence.
If we were to descend to particulars, we
should be at once convinced of the indigency
of the higher order of animals, in the propagate
EVOLUTION OF LIFE. 65
ing power which they possess, with relation to
those of a lower class, and more especially to
vegetables in general. An elephant seldom
produces more than one young in the course of
two years ; while, on the contrary, rabbits propagate
every six weeks. This power increases,
in an infinite degree, as we descend in the
scale of animation. Hens frequently lay forty
or fifty eggs in one season, and when we reflect
that pigeons can hatch nine times in one year,
it appears that they can multiply their species,
in four years, near fourteen thousand times.
In the amphibia, this prolific power is equally
observable. There was a turtle killed in London
a few years since, out of which, two thousand
five hundred eggs were obtained : the
quantity of ova that fish evolve is so immense,
that they are often known to cover, for the space
of many leagues, the surface of the ocean. We
all see the multitude of maggots that are generated
in rotten cheese, and of different insects
that are produced in different substances which
are undergoing the process of putrefaction
and fermentation ; a single mite has been
known, in the course ofa few days, to re-produce
its species at least one thousand times.
If we cast our eyes to the surface of the
earth, we shall be convinced of the prolific
powers of vegetables, <and of the lower order of
animals, with relation to those of a higher class.
66 EVOLUTION OF LIFE.
One single plant of elecampane will frequently
produce, in one season, three thousand seeds ;
the poppy, three thousand four hundred ; the
sun-flower, four thousand ; the tobacco plant
has been known to bring to maturity forty
thousand three hundred and twenty seeds.
The astonishing power, with which God has
endued the vegetable creation, to multiply its
different species, is more particularly manifested
in the elm. It is observed by a learned
commentator and critic,* that the elm produces
upwards of one thousand five hundred millions
of seeds, each of these seeds having the power
of producing the same number. How astonishing
is this produce ! At first, one seed is deposited
in the earth ; from this one, a tree
springs, which, in the course of its vegetative
life, produces one thousand five hundred and
eighty-four millions of seeds, this is theirs*
generation. The second generation will amount
to two trillions, five hundred and ten thousand,
and fifty-six billions. The third generation
will amount to fourteen thousand six hundred
and fifty-eight quadrillions, seven hundred and
twenty-seven thousand, and forty trillions ! And
thefourth generation from these, would amount
to fifty-one sextillions, four hundred, and eightyty-
one thousand three hundred and eighty-one
* Dr. CLARKE’S Commentary on Gen. i. 12.
EVOLUTION OF LIFE* 67
quintillions, one hundred and twenty-three
thousand one hundred and thirty-six quadrillions
!
Whatever the imagination of poets may have
conceived of the loves of plants, or whatever
may have been asserted by LINN^.US of the
SEXUAL SYSTEM, the truth of this system continues
to be very questionable and uncertain.
The various modes, by which the species are
multiplied, and the destitute state of nervous
energy in the parts which are concerned in that
process, decidedly prove, that they are not only
insensible to any feeling, but altogether unconscious
of the actions which they perform. If
any nervous arrangement has an actual existence
in them, it does not extend throughout the
whole of the system, but is confined to the
efflorescence alone, at the particular times,
when the corolla is unfolded, and when the
system is about to fultil the end of its existence,
in the production of fructification. How
debile and limited must this nervous power be
conceived, when we reflect on the immoveable
spot to which vegetables are fixed, and the
short life which the efflorescence is suffered to
enjoy. It is no sooner arrived at adolescence,
than its acme of perfection is attained, and the
period of caducity immediately ensues. The
system proceeds from germination to fructification,
from fructification to death, in a regu-
F2
06 EVOLUTION OF LIFE.
lar and unbroken tenor, without possessing, so
far as we can detect, any opposing or controling
power, by whose energy the vital actions
can be arrested or suppressed.*
By the condition of animals, as well as of the
human species itself, during sleep, ‘and more
especially as they subsist in the foetal state,
some idea may be formed of the nature of
vegetable existence. The foetus extracts nourishment
from the maternal system, to which it
is attached, as a cherry does from the parent
stock. Although it possesses organs of sense,
it is destitute of feeling ; and with organs of
consciousness and of apprehension, it neither
reflects on the means of supporting itself, nor
is sensible of its own existence ; an animal, in
the foetal state, is situated in a manner exactly
similar to an adult in a profound sleep, and
both resemble vegetable life. During sleep, all
the organs which subserve to the growth and
nutrition of the system, perform their functions
more perfectly, than they are found to do, during
a state of watchfulness. Respiration and
digestion, absorption and circulation, secretion,
as well as excretion, go on without the
energy of the will ; the energy of the will has a
tendency to impede these different functions in
* Mr. A. KNIGHT has decidedly proved that vegetables
have no sensation.
EVOLUTION OF LIFE. (59
their course : it is not the existence of the organs
which subserve to these purposes, which
constitutes the distinguishing characteristic between
vegetables and animals, as Mr. HUNTER
imagined. However varied the organs may
be, which subserve to the growth and support
of the system in animals, from what they are in
vegetables, they all subserve to the same use,
and are regulated by the same laws : in all,
they are intended to build and to erect a system
in the best possible way, fitted and adapted to
perform certain determinate ends. It is because
the ends are different in each, that there
exists a diversity in the means. While the
existence of a sensitive principle, of which a
nervous system is the immediate recipient, appears
to form the distinction between animals
and vegetables, and not the existence of a
stomach, as Mr. HUNTER supposed, so the
magnitude of the brain with relation to the
organs of sense, forms the principal grounds of
difference between irrational and rational animals,
between brutes and the,human species.
The physiologists who first directed their
attention to this subject, proceeded on wrong
data ; instead of comparing the magnitude of
the brain, with relation to the size of the nerves
which proceed from it, they compared the
relation which it bore to the aggregate weight
of the body. It is not, therefore, surprising.
70 EVOLUTIONS OF LIFE.
that from these data, the most inconclusive
reasonings should have been made. To Professor
SOEMMERING considerable merit is due,
for having put the subject upon its true footing;
he it was, who first pointed out that the magnitude
of the brain, with relation to the nerves of
sense which proceeded from it, was the true
point whence the comparison was to be made ;
it was from this mode of investigation, that it
was found, that, although the most irrational
systems have the largest nerves of sense, they
have the smallest brain ; and, on the contrary,
that the highest orders of animals have the
largest brain with organs of sense comparatively
small,
BARON HALLER observes, that in a boy six
years old, whose body weighed fifty pounds,
the brain weighed two pounds, three ounces,
and a half; and that when it is fully developed,
it may be generally averaged, in each individual,
at the rate of four pounds.. BLUMENBACH asserts,
that the largest brain of a horse which he
ever saw, weighed only one pound four ounces.
REDI says, that the weight of the brain of an
ox to that of its body, is, as 1 to 1154; and a
shark that weighs 300lbs. it is said, has a brain
that does not weigh more than three ounces.
In the snail, the brain is composed of a congre^
gation of nervous fibrils, which terminate in a
gort of trunk, of a semicircular structure. In
EVOLUTION OF LIFE. 71
the larvae and zoophytes, and that large and
intermediate class of beings which connect the
animal, with the vegetable, kingdom, although
there is a structure, of a nervous appearance,
which is expanded over the whole surface of the
body, the existence of a brain, as a distinct organ,
is not discernible. As we descend from the higher
to the lower orders, we shall find that the magnitude
of the brain progressively decreases from
the white, to the black, of the human species,
from bipeds to quadrupeds, from quadrupeds
to birds, from birds to fish, from fish to
insects, where all traces of the existence of
brains and nerves, as organs, separate and distinct,
are altogether lost. The extensive power
in them, which the organs of- sense possess, is
more especially calculated to attain those ends
which, in the great scheme of providence, they
are destined to perform : the sense of want and
of appetite, which the organs suffer, constitutes
the impulse whence all their motives spring, and
to the relief and gratification of which, all their (
actions are especially directed. It is the power
whence the impulse arises which may be called
instinct. It constitutes the principle, by the ‘
energy of which,, certain organs are employed
to perform certain determinate actions, with a
view to certain ends or consequences ; they are ,
impelled by natural and blind impulse, which
72 EVOLUTION OF LIFE.
they know not, and cannot resist; by fatal necessity,
by brutal appetite.
Beings, such as these, cannot be considered
accountable for the actions that they perform,
any more than vegetables, which neither feel,
nor reflect. These actions are always limited
and directed to the narrow limits of their particular
instincts ; however varied, in their direction,
in different beings those instincts may be,
they are invariably the same throughout the
life of the same individual, as well as of all belonging
to the same class ; and, are at once perfect,
not by previous instruction, or even imitation,
but by a sort of intuitive power which is
possessed throughout the whole race of animated
beings. Every particular class, therefore,
performs the same actions in the same way, and
with the same degrees of perfection. The
works of animals are, indeed, like the works of
nature, so perfect in their kind, that they can
bear the most critical examination of the mechanic
and mathematician. No human art has
ever been able to imitate the wonderful machinery
constructed by the power of the bee, or
the web, by the tentacula! of the spider. It has
been well observed by Dr. RE^D, (wrhose
authority upon these subjects must carry with
it great weight) that every manufacturing art
among men, was invented by some man, improved
by others, and brought to perfection by
EVOLUTION <JF LIFE. 73
time and experience: the arts of man vary in
every age and in every nation, and are known
only to those men who have been taught; but
the manufactories of animals differ, in toto, from
those of man. No animal of the species can
claim the invention, and no one ever brought
any one improvement, or any variations from
the former practice ; every one of the species
has equal skill from the beginning, without
teaching, without experience, and without habits,
and every one has its art by a kind of
inspiration ; not inspired with the principles or
rules of art, but with the ability of working it
to perfection, without any previous knowledge
of its principles, rules, or ends.
The analogy, therefore, which exists between
the vital organs of animals, and the whole vegetable
kingdom, although it proves that the living
principle, by which the system of each was
formed, is of the same nature in all, is, nevertheless,
distinct from it, in being destitute of
organs of sensation or of consciousness. The
actual existence of organs, not only of sensation,
but of consciousness, in them, shows that
they both feel and think ; the merest worm that
crawls upon the surface of the earth, feels ‘ a
consciousness of pleasure and of pain, of appetite
and gratification, of security and of danger;
it not only seeks for the means of satisfying its
wants, but is conscious of the danger to which
74 EVOLUTION OF LIFE.
it is exposed from different animals, by whom
it is devoured or destroyed ; we, therefore, see
it get out of their reach. Mr. Locke observes,
” that animals seem to have perceptions of
particular truths, and within very narrow limits,
the faculty of reason ; but we have no reason,”
says he,
” for supposing that their natural operations
are performed with the view to consequences,
and therefore not the result of a train
of reasoning in the mind of the animal.” So
far, however, from this assertion being well
founded, all the voluntary motions, on the contrary,
which animals perform, to me appear the
result of a motive which exists in them, and
that the organs which they employ, have objects
for their end. The acquisition of food and of
intercourse, are the consequences of the natural
actions which every animal displays ; it is
the nature of this impulse or motive, through
the power of which those actions are produced,
that constitutes the distinction in the appetites
of different animated beings, to the gratification
of which all their pursuits are especially directed.
If I were to enter into a particular examination
of the corporeal means which are possess*
ed by the higher and lower order, I should be
led to acknowledge the total indigency of the
one, and the self-sufficiency of the other. While
vegetables shed their seed upon the soil, and
EVOLUTION OF LIFE. 75
fish deposit their spawn upon the waters, and
different birfls lay their eggs upon the sand,
such is the perfection of the living power which
they possess, that the aptitude in the medium
alone, in which they are placed, is, in general,
adequate to answer every purpose of their
evolution and growth. In the higher orders
of beings, the evolution of the offspring
during the whole period of gestation, is totally
indigent of parental aid. The difficulty
and concomitant danger of parturition, progressively
increases, from the most simple to the
most complicated system, from brutes to the
human species, and more especially from savage
to civil life. The labor and anguish of the mother,
until that awful and important process is
accomplished ; the lamentations and cries of
the infant when born ; the total incapacity to
assist itself, or to obtain its own necessary
wants, all prove the imperfection and indigency
of the human frame.
The sense of want which the organs feel, and
the impression from external objects, are nearly
alike in the infant state of savage, as of civil
life ; all seem to have the same desires and the
same pursuits, and at that early period, human
life is entirely of an animal nature. It is equally
the case with savage nations in general ;
among them, the rules of social order are entirely
inverted; the weak falls a prey to the strong;
76 EVOLUTION dT LIFE.
women, instead of being the companions, are
the slaves ofthe men ; rapine is no crime, where
honesty is no virtue; killing is no murder,
where personal revenge is allowed ; and neither
adultery nor fornication constitutes a crime,
where promiscuous and incestuous intercourse
is tolerated. Among them, intemperance is
preferred to sobriety,^-ignorance mistaken for
knowledge, the passions and appetites of
youth preferred to the wisdom and virtue of
age. This state of degeneracy and of corruption
may be considered the condition of man,
when he allows himself to follow the pursuits
alone, to which he is impelled by the force of
sensual inclination. ST. PAUL, in his letter to
the Romans, tells them, that it was by this
condition that they were degraded and debased;
that they were impelled to act by the force of
passion without reason ; ^that they had the
propensities, and followed the pursuits of the
brute, without his instinct ; that they led, in
fact, a life of sense without reason. The apostle:
also tells them, that there was a law in their
members, which warred against the law of
their minds ; that the good that they did, they
would not, but the evil which they would not,
that they did. A condition, such as this, is not
the condition for which man was designed ; it
proves what he may, not what he ought to become
;
it proves, that the more he indulges his
EVOLUTION OF LIFE. 77
senses, the power of his mind becomes progressively
weakened; that instead of attaining the
prerogative of being a free agent, he continues
in the condition of a child, or of a man who
lives like a brute, impelled and chained down
by that fatal necessity of sin which he cannot,
in that state, avoid.
Miserable, indeed, would be the condition
of man, if the fatal necessity to obey the force
of passion to which the sensualist and the depraved
are doomed, extended to the whole
race ; if he were destitute of the power of directing
and of regulating the ideas, which, in
consequence, arise ; or, ifnone subsist, but those
excited by objects of sense. It has been well
observed by Dr. GJREGORY, on the inconsistency
of thefatalists, that if this were the case,
there could be no variety, and scarcely any
change in the pursuits of men ; the thoughts
would fio\v from each other, in one uninterrupted
series, and man could not be an accountable,
and scarcely a rational, being. It is, however,
very plain that we have a power of interrupting
a train of thoughts, and of dwelling more intensely
upon particular ideas, and even of
occasionally directing our reflections and contemplations
into new channels ; and this power
alone, is sufficient to constitute mail, a free
agent.
Although there are many parts in Mr.
78 IVOLUTIOX OF LIFE.
LOCKE’S book, that have a tendency to favor the
doctrine,
” that human actions are the result
of a necessity, which the individual cannot prevent,”
it is not, however, always the case ; on
many occasions, he is either driven or led to
acknowledge the free agency of man :
” This
I think,” says Mr. LOCKE,
”
is at least evident,
that we find in ourselves a power to begin or
forbear, continue or end, several actions of our
minds, or motions of our bodies, barely by a
thought or preference of the mind, ordering, or,
as it were, commanding the doing, or not doing,
such or such a particular action. The power
which the mind has, thus to order the consideration
of any idea, or the forbearing to consider
it, or to prefer the motion of any part of the body
to its rest, and vice versa, in any particular instance,
is what we call the will.” It is the particular
nature of this intellectual power in man.
which constitutes the distinguishing characteristic
between excellence and mediocrity, that
ought to mark out the individual from the species,
the man from the brute, and form the
real source of distinction in the attributes by
which different men ought to be estimated. It is
to the motives which spring and originate from
the mind, more than from the effects which are
produced by the organs as the instruments, that
we ought to attach merit or disgrace to them for
the actions they perform. It is from principles
EVOLUTION OF LIFE. 7
such as these, that we ought to conclude that
the man of science is to be preferred to the
artist; the wisdom and temperance of age,
to the appetite and passion of youth ; and
civil life to either savage or brutal. Intellect
bears the same relation to intellectual
things, as sense does to those that are material ;
and, as intellect is better than sense, it must
evidently appear, that intellectual pursuits are
to be preferred to those which are sensible or
material ; and, finally, that the objects of intellect
cannot be derived from objects of sense ;
otherwise, they would be subordinate, and not
superior to sensible things.
It is by the proper exercise of these
powers of intellect, directed to those objects
which seem to be congenial to its nature,
that man feels conscious that he constitutes the
first of all generated beings ; that although excited
by appetite and sense, he is nevertheless
able to resist, to subdue, and even to act in
opposition to those wants ; often compelling the
body to fast, when it craves for food, to receive
medicines which convey impressions nauseous
and painful ; to expose itself to the inclemency
of the seasons, and to various dangers;
to labor and to fatigue ; and patiently to submit
to death itself :
Decus et decorum cst pro patria mori,
80 EVOLUTION OF LIFE.
It was this sentiment which prevailed in
Cato’s mind, that enabled him to despise the
danger and the disgrace to which he was exposed
by the tyranny of C^SAR ; he felt that
the soul, secure within itself, could smile at
the drawn dagger, and defy its point ; that it>
could flourish in immortal youth, unhurt amidst
the war of elements, and the crush of worlds.
Admitting the truth of these observations,
(which must, indeed, have been apparent to
every reflecting mind) the conclusion presses
itself irresistibly upon the understanding, that
the end for which man was created, is totally
different from that of any other being.
Instead of being confined, like vegetables,
to the production of the species ; or, as in
the brute, to the gratification of the senses;
these objects constitute, in man, the lowest of
the ends which he is designed to attain : those
which are most congenial to his nature, and
which form the true end of his existence, more
especially consist, in the perfection of his
MIND, in order that he may be qualified to,
adore the ALMIGHTY, and become acceptable
to him.
While the attributes of vegetables consist in
the living and vegetative principles alone;
those of brutes in the vegetative, the sensitive,
and the irrational ; man, in addition to
these, possesses the intellective also ; and may
EVOLUTION OP LIFE. 81
be defined,
” a rational soul, in an animal body,
which it employs as its instrument.”
Say, why was Man so eminently rais’d
Amid the vast creation ? why empower’d
Thro’ life and death to dart his watchful eye,
With thoughts beyond the limits of his frame ;
But that th’ Omnipotent might send him forth
In sight of Angels and immortal mind,
As on an ample theatre, to join
In conquest with his equals ; who shall b
The task achieve, the course of noble toi
By wisdom, or by mercy, pre-ordain’d.*
Might send him forth the sovereign good
To chase each meaner purpose from his b
And thro’ the mists of passion and of sense,
And thro’ the pelting storms of chance and pain.
To hold straight on, with constant heart and eye
Still fixt upon his everlasting palm,
The approving smile of heaven 1
Akenside’s Pleas, of Imag*
* No doctrine has ever, perhaps, been more completely
mistaken, than that of predestination. By many, it has been
thought, that some there were, who were elected and predestined
to enjoy every blessing in this life, and happiness in the
next, notwithstanding the wickedness of their conduct ;
others again, that were doomed to suffer every misfortune in
this state of existence, and to endure eternal damnation hereafter,
however meritorious their conduct might have been.
If this explanation were true, instead of the Almighty being
what he is, all-bounteous, wise, and just, and the source of
all goodness ; it might rather be supposed, that he is the very
devil himself, and the cause of all evil. Great, indeed, is
the error ot” those who judge in this way. It is very true
G
82 EVOLUTION OP LIFE.
Such, however, is the immeasurable distance
which exists between the universal Intellect of
Almighty God, and the mind of man, between
the Creator, and the creature, between
the infinite Being, and the being which is finite ;
that the most perfect intellection, which proceeds
from the energy of the purest Intellect, is
as the dust of the earth, when the one is compared
with the other ; his attributes can no more
be apprehended, by matter, in general, which
is destitute of life, than by vegetables, or by
brutes in particular ; by vegetables., which
possess vitality without sensibility ; or by
brutes, who have sensibility without intellect.
The brute himself, no more than man, who
leads the life of a brute, whose whole thoughts
and actions are directed to the gratification of
his senses, and whose senses are never gratified
until they are surfeited, can never, in that degraded
state, obtain any perception of spiritual
things, any more than those among us, who
believe that there subsists within them, no other
that, in the general scheme of Providence, predestination is
a’ doctrine especially foretold by revelation, that shall be the
lot of the elect ; but the elect grossly deceive themselves, if
any there be who suppose themselves pre-elected ; the only
way they can make their election sure> is by religion, and the
performance of the duties it enjoins. It is not, therefore,j?flrticular
men that are elected, but men ofa particular description*
which description the gospel has pointedly designated.
EVOLUTION OF LIFE. 83
power than what arises from the mere matter
of which they are composed ; the one can no
more have communion with spiritual things,
than the most ignorant and uneducated among
the sons of men, is able to understand the
highest branches of human knowledge ; to obtain,
for example, a perfect knowledge of geometry,
although totally ignorant of lines and
figures ; of all languages, without possessing
any apprehension of sound ; and of all sciences,
without any perception whatever of the truths,
or principles, on which they are founded.
Between the lowest degrees of instinct and
of sense, the offspring of animal existence and
the mind of man, there can be no understanding,
because there is no analogy between them ;
the most irrational animal is no more able to
apprehend the knowledge of the most rational
man, than the most rational man is able
to imitate the instinct of the most irrational
brute; the cause lays in the ignorance of the one,
and the wisdom of the other. No correspondence
whatever can subsist between beings
whose natures are separated by a chasm so
widely different. It is with a view of adapting
our meaning to the level of the understanding
of the brute, that we converse with them in
a silly unmeaning manner ; to them a wise and
intelligent conversation would be unintelligible
and foolish. Children, therefore, or men who
G 2
84 EVOLUTION OP LIFE.
act like children, have animals more immediately
under control, than the philosopher
who is replete with wisdom and knowledge.
If God, therefore, had not manifested some
portion of his attributes, by means which are
on a level with the capacity of the human race,
man must, for ever, have been ignorant of his
Maker. He, therefore,
” tvho at sundry times,
and in divers manners, hath spoken unto the fathers
by the prophets, hath, in these latter days,
spoken unto us by his Son/’ made of the same
materials as ourselves, born of a woman, obnoxious
to human wants, and liable to the same
dangers.
Although it is greatly to be deplored, that a
large proportion of the world continues deprived
of the benefit of the Christian dispensation,
there are few people congregated together
into one society, wlro are destitute of religion;
of a belief, that there exists some being superior
to themselves, and who, consequently, becomes
the object of their adoration and worship.
The very act of humiliation which they
offer constitutes them religious beings ; whether
the object of their adoration be symbolised by
the sun, or by the moon ; by a stock, or a
stone. It is by the particular doctrines which
particular religions enforce, that, men are directed
to particular modes of worship, and
EVOLUTION OP LIFE. 85
whence the moral conduct of the individual
takes its bend.
It is the especial object of the Christian dispensation
to teach man to have a knowledge of
himself, in order that he may know what he
really is : that, although he possesses within
himselfa soul, immortal and divine, this divine
nature is, nevertheless, full of corrupt affections,
from the depravity of the animal constitution,
by which it is defiled; that he is less
disposed to acquire the perfection of the one,
than to indulge the impulse of the other,
Christianity will teach man, that he is, by nature,
born in sin, and the child of wrath ; that, instead
of resisting the allurements of passion,
and of vice, he is prone to yield to their influence
; that instead of resisting, like the oak of
the forest, the hurricane force by which he is
assailed, he bends to temptation, like the willow
to the air ; and, that he is incapable of becoming
acceptable to the Almighty by his own
works.
Notwithstanding the fallen condition of man,
he is not left altogether destitute of attaining
the end for which he is designed. If he employs
the means, they are always within his
reach. In order, however, to obtain regeneration
from sin, it is absolutely necessary that he
should give up the ” old man,”
” be born again,”
>’ live in newness of life,” and in the simplicity
86 EVOLUTION OF LIFE.
of a child, follow the means of salvation which
are proclaimed in the gospel. By constant
watchfulness and humility, by abstraction from
passion and from sense, by self-examination
and repentance, by imploring, before the
throne of grace, aid of the Holy Spirit, man
attains that peace of mind which surpasseth all
understanding, that assimilation of soul to
the divine nature, which enables him to commune
with his God, and have his redemption
from sin secured, through the efficacy of his
Saviour’s atonement.
It is the efficacy of his faith in this atonement,
which enables him to triumph over indigence
and oppression, and rise in full vigor, when
appetite is no more ; to bear up against the toils
and turmoils of this life ; to smooth the brow of
care, and dispel the gloom of despondency ;
to sweeten the bitterness of grief, and lull agony
to rest. Religion ought, therefore, to consti.
tute the base of every national establishment;
and be the rock, which the whole nation, as
one man, ought to grasp. It ought to form the
main spring of man’s actions, the beginning, the
middle, and the end of his pursuits; and it is
humbly hoped, that, although the glad tidings
of salvation have been confined to particular
people, the efficiency of the atonement will
extend to all nations, kindreds, and languages,
/ C/
C IIAFTER V.
ON THE DOCTRINE OF MA
SECTION I.
The Materiality of Life examined arid refuted.
NOTWITHSTANDING the vague and indefinite
nature which I have proved, matter, in general,
bears, in its relation to the powers and attributes
of life ; notwithstanding the passive
condition to which it is doomed, the regular and
circumscribed motions which it is made to suffer,
or sustain ; it has not prevented a set of
men, who debase the very name of philosopher,
which they assume, by the appellation of Materialists,
from affirming and concluding, that
matter, in general, possesses the inherent power
of converting itself into organs ; in fabric, most
delicate ; in action, most extensive ; and in
form, most diversified : that by the congregation
of these organs, one whole system is constituted;
that the result of this organisation
forms life, and that out of this organised life,
88 DOCTRINE OF MATERIALISM.
action and motion are produced: so that
matter is the primary cause of which life is the
secondary effect.
As varieties of the same species, as chips cut
out of the same block, educated in the same
school, and instructed in the same principles,
are the oxygenous philosophers : physiologists
of a more modern date, and of feelings far
more refined. They have taken great offence
at the baser materialists, for supposing that
matter, in general, however gross, however
imbecile and inert it may actually be, could
possess any inherent power of kneading itself
into organs, endowed with animation and
spontaneous action. Although these philoso-^
phers virtually adopt the doctrine of the baser
Materialists, they vainly think they refine the
doctrine by limiting this important property to
oxygen in particular, instead of extending it to
matter in general.
It is, therefore, necessary to explore the
sources whence oxygen is produced, and the
manner in which it is obtained. Oxygen is
found in, and obtained from, the oxydes, or
calces of metals, and semi-metals ; especially
of red-lead, and the black calx of manganese:
it is more especially secreted by the last order
of animated beings by the vegetable kingdom
in general, as excrementitious and foreign. It
is this particular air this oxygenous matter
DOCTRINE OF MATERIALISM. 89
which vegetables, in the day time, are constantly
discharging from the whole external
surface of their foliage as urinous and feculent ;
and which the aberrations of these pure defecated
philosophers suppose, constitutes the
principle of life, in which all living power essentially
resides, the immediate and proximate
cause of irritability in man ! ! !
The rational mind turns away with nausea,
and with aversion, from the contemplation of
causes, that lead to such unseemly conclu^
sions ; it receives, with becoming indignation,
and is disposed to hold up to derision, and to
scorn, the folly of those pretenders to physiology,
who know not how lo separate the subject
matter of a body, from the power by
which it is governed, and to which it is wholly
subservient. The oxygen, before it is received
into the system, is as absolutely dead as any
particle of food which is introduced into the
stomach,
I flatter myself that these strictures will not
be considered too severe, when I proceed to
point out the intemperate and abominable system
which these visionary doctrines have produced.
I am naturally led, as an immediate
effect flowing from cause, to investigate the
Ttrunonian system a system which, I am
grieved to say, has generally prevailed at
home, as it does universally abroad ; not only
90 DOCTRINE OF MATERIALISM.
in theory, but in practice also. Instead of
grasping, and adopting the doctrine of the Materialists,
in its native dress, and ascribing to
the Almighty Power of matter, the essential
and original attributes of life ; it is to the residuary
and ultimate effects only, which matter
evolves, whence life originates, and to which it
is referred : instead of making life an origin,
and a principle, Dr. BROWN, supposed it to
consist in a forced state ; that it is an effect
only instead of a cause : he makes life to begin
at its end ; to consist in what he calls excitement
; and that this excitement, or life, is the
effect of which the exciting powers, acting on
the excitability, are the cause.
If this relationship actually subsisted, between
the exciting powers, and the excitability;
if the result of both, were the true cause
of life, life would then, indeed, be, what he
foolishly affirms it would be, a forced, not an
original state; an effect, not a cause ; an end,
not a beginning ; instead of animated beings,
being, by necessity, forced to die, they might,
by the power of excitation, be forced to live ;
so that, by the proper application of his stimuli,
he might perpetuate life for ever and ever.
Life might be changed and varied, exhausted,
augmented, and renewed to a high, or to a low
state, back again from a high to a low one, in
proportion as he chose to infuse into the system
DOCTRINE OF MATERIALISM. 91
his diffusible, or fusible stimuli, brandy or
water heat or cold oxygen or azote pleasure
or pain joy or grief.
Nothing, but a perverted way of thinking,
could have led philosophers, such as these, to
ascribe to matter, independently and abstractedly
from the energy and participation of life,
the power of organisation ; or, to have referred
to this organisation, the source of life, as its
cause. It is evident, indeed, that these gentlemen
move in an inverted order, and end where
they ought to begin ; they begin, by making
power to arise out of weakness ; symmetry
and order, from that which is naturally formless
and motionless ; and, finally, design and intelligence,
the attributes of things void of all consciousness,
and destitute of all sensation. Instead
of making organisation the effect of life,
they make life to be the effect of organisation ;
instead of making the phenomena of organisation
the end, they make it the primary and efficient
cause, in which life virtually originates
and abides, the source of life, indeed, at its
termination.
This silly hypothesis is at once refuted, by
the total impossibility which exists, of giving
a rational answer to this simple question ; to
the question which I have often had occasion
to put to many of our physiologists, who entertain
these opinions; What is the cause of
92 DOCTRINE OF MATERIALISM.
organisation ? What is the cause that the multitude
of seeds, and of eggs, which are deposited
in the same soil, and exposed to the same
air, are able to act upon the different substances
by which they are surrounded : to
convert them from a dead to a living state;
from a state of dispersion, to a state of combination
; from a tabula rasa to organisation and
form ; from chaos itself into symmetry and
order ; and from a multitude of separate parts,
into one whole system, total and complete?
Although I have frequently heard much ingenuity
displayed in reasoning upon this superstructure,
I have often witnessed much folly
and ignorance, in attempts to account for the
foundation of it. Instead of supposing that the
different organs, which different beings possess,
are the recipients only of these different powers,
and that the matter of which they are composed,
would, without them, be as imbecile and inert
as the shoe is without the foot, or as the musical
instrument is, without the art, or skill, of the
musician : it is to the matter alone that the
whole power is referred. An hypothesis, such
as this, is not more absurd than that which is
assumed, that the organs with which living beings
are endowed are the cause, primary and
efficient, of which vitality and intellect are the
effect. With as much reason might it be affirmed,
that the pen with which I write, moves
DOCTRINE OP MATERIALISM. 93
my hand, instead of my hand moving the pen ;
that the top moves the whip, instead of the
whip moving the top; that language is the
cause, of which rationality is the effect ; that
the nucleus of the earth, as well as the dirt and
mud upon its surface, are the causes of which
vitality is the effect; that the whole material
world is, in fact, the great first cause, of which
the Almighty is the secondary, or instrumental
cause; that is to say, that the second cause, is
the cause of the first, and that the effect produced
is the cause of the causes.
It evidently appears, that the materialists, instead
of attributing inertness to matter, make it
the first cause of motion ; they behold it destitute
of form, and of fabricating power, and yet
refer organisation to its imbecility ; they see it
matter impelled, and yet they make it impelling
matter. Instead of considering it the last and
lowest of things, they make it the first and the
best ; instead of separating the cause from the
effect, they constantly confound both together ;
they mistake the thing produced, for the power
producing ; the fact, (the thing done) for the
law. Instead of putting confusion into order,
they put order into confusion. The consequences
of this false philosophy are manifested
by the puerile knowledge which we possess,
being entirely circumscribed to effects only,
without any knowledge of cause;- to end*
04 DOCTHIKE OF MATERIALISM.
without means ; to history without definition;
to definition without axiom ; finally, to a nomenclature,
which never designates the nature of
the thing which it is designed to proclaim.
It is high time that absurdities, such as these,
should be banished from our schools of science,
and the rising generation rescued from the contamination
which they, in consequence, suffer.
So long, however, as the false hypothesis continues
to prevail, that matter is the cause of
which life and soul are the effects, no hopes
whatever can be entertained of any philosophical
reformation. I, nevertheless, will maintain,
that these opinions are not the offspring
of ignorance, simply ; but of two-fold ignorance,
of that state of ignorance, by which
men persevere in error, without being conscious
of it, and which sears the mind against conviction
and reproof.
SECTION II.
The Materiality of the Soul examined and
refuted.
THE erroneous opinion which the Materialists
entertain, respecting the nature of life, or
vitality, are even more striking, when they are
applied to the higher principle which man posDOCTRINE
OF MATERIALISM. 95
sesses of intellect, or soul. Instead of considering
the organs which the principle of life
has elaborated, as the mere recipient of its
power, as the secondary, or instrumental
cause, by the energy ofwhich, ratiocination, and
voluntary motion, are produced, it is to the
organisation alone subsisting as a cause, to
which the essence and power of soul are ascribed.
Nothing, however, can be more erroneous.
The error has been acknowledged by
the best, and by the wisest men, that have ever
flourished, in antient or in modern times : it
has appeared to them that the attributes of
mind, and of matter, are altogether different
and distinct from each other; and that no
modification of matter whatever, could account
for the formation of the soul. It must
be apparent, that if the soul is material, that
like the universal attribute which belongs to
matter, it must be composed of parts ; and,
that if it contains parts, that it necessarily
must be divisible ; that if it be divisible, it
must likewise be decomposable and resolvable ;
and if it be decomposable, it must be destructible
; and if it be destructible, it must be a composite
; and if it be a composite, it must have
triple dimensions of length, breadth, and thickness,
as the common attributes belonging to
matter, in general. If this were the case,
the accumulation of ideas, would pecessarily,
96 DOCT&INE OF MATERIALISM.
be followed by an increase in the bulk of
the organ, by which those ideas were received.
It is, however, very evident* that
so far from the attributes of the mind producing,
or increasing, the bulk in the body,^-the
body, by the exercise of the mind, is rendered
more active and energetic ; that, instead of manifesting
to the organs of sense, any sensible
qualities, the mind is altogether insensible to
them : and, instead of being nourished, like
the organs of nutrition, the food wkich is congenial
to its nature, is such alone as flows from
reason and understanding. It is, therefore,
legitimate to conclude, that the soul is not corporeal,
but immaterial ; that it is simple, and
without parts ; and, consequently, indestructible
and immortal: for dissolution can only
arise from the separation of one part of a
thing from another, but which can never take
place in a principle which is essentially simple.
If the attributes of mind depend on organisation,
how is it possible that any permanent idea
of things can take place? for ideas could never
survive the duration of the particles of matter
which subsist in the organ, by which those
ideas were received. Memory could form no
part of such a system.
Experiments, however, go to prove that the
most solid, in common with the softer and
more fluid parts of the body, are in a state of
DOCTRINE OF MATERIALISM. 97
constant flow and change ; and, that animals,
whose bones had been tinctured and colored
red, by the madder with which they had been
fed, had recovered their usual complexion in
the course of seven years, after the madder had
been discontinued. We may, from this infer,
that as the more tender parts of the system are
more rapidly carried away, that, consequently,
the recollection of past events could never extend
beyond that period. Cases have also occurred,
when patients, in consequence of disease,
have forgotten recent events, and, nevertheless,
possessed a perfect recollection of
those which had happened long before. A curious
instance of this kind happened to a man
brought to St. Thomas’s Hospital, with a concussion
of his brain, who, by proper treatment^
recovered. It was observed, during the progress
of his cure, that although he spoke to the
attendants, it was in a language which none of
them understood ; a Welsh milk-woman, who*
came into the ward, having heard him speak,,
entered into conversation with him ; it was then;
found that the man, by birth, was a Welshman,
that he had left his native land in his youth,
that he had forgotten his mother tongue, and
that, for the last thirty years, he had spoken the
English language alone. Since the accident
from which he had recovered, he only remembered
the events of his younger days, and
m
98 DOCTRINE^OF MATERIALISM,
had entirely forgotten the English language,
and the occurrences of the latter years of his
life.
The opinions which are entertained respecting
the materiality of the soul, have not even
the merit of novelty in them ; they had been
entertained by different men, at remote periods,
as well as in more modern days : by none, however,
have they been proved to be false and
absurd, (by arguments more legitimate,) than
by Dr. S. CLARKE, a century and a half ago,
in the controversy which he maintained with
Mr. DODWELL, the materialist. In the hope
that the force of his reasoning may produce the
same conviction to others that it has done to
me, I shall, for that purpose, select a passage
on the subject from his valuable work :
” That
the soul,” says he,
” cannot possibly be material,
is demonstrable from the single consideration
of bare sense or consciousness itself; for
matter being a divisible substance, consisting
always of separable, nay, of actually separate
and distinct parts, it is plain that unless it
were essentially conscious, (in which case every
particle of matter must consist of innumerable
separate and distinct consciousnesses,) no system
of it, in any possible composition or division,
can be one individual conscious being.
For supposing three or four hundred particles of
matter, at a mile or any given distance one
00CTRINE OF MATERIALISM. 9$
from another, is it possible that all these separate
parts should, in that state, be one indivi-*
dual conscious being? Suppose then all these
particles brought together into one system, so
as to touch one another, will they thereby, or
by any motion or composition whatever, become
one whit less truly distinct beings than
they were, when at the greatest distance ? How
then can their being disposed in, any possible
system make them one individual conscious
being ? If you would suppose God, by his
infinite power, superadding consciousness to
the united particles, yet still these particles, being
really and truly as distinct beings as ever,
cannot be themselves the subject in which that
individual consciousness inheres : but the con-*
sciousness can only be snperadded by the addition
of something, which, in all the particles,
must still itself be but one individual being.
The soul, therefore, whose power of thinking is
undeniably one individual consciousness, cannot
possibly be a material substance.” If, however,
it be supposed that the soul is a material
substance, and that the brain, or any other
part whatever is the organ where it resides, it
must evidently follow that the quality of this
organ must be made up of the individual qualities
of all its parts : for example, the bulk of
the body is made up of the sum of the magnitude
of all its parts ; its motion is nothing but
ttl
100 DOCTRINE OF MATERIALISM.
the sum of the motion of all its parts ; and if
thinking or consciousness can be supposed to
be a quality inherent in a system of matter, it
must be also the sum and result of the thinking
and cogitation of all its separate parts. We
should, therefore, have as many distinct consciousnesses
or minds, as there are particles of
matter of which the brain consists, an idea
fanciful and false ; for composition or division
of magnitude varied, in an infinite manner,
can produce nothing in the whole system
but magnitude ; composition, and variation
of motion, nothing but motion ; composition,
and variation of figure, nothing but figure ; and
so of every other quality whatever. If, however,
it be supposed that not the brain altogether,
but one particle of it alone, is the seat of
the soul, &c. that one particle being divisible
into two, there must, consequently, exist two
souls, not one soul, in the same system, and
that each must think apart, and not together.
ON SENSATION AND ITS OBJE
IF we proceed to examine the relation which
exists between the impressions made by external
objects on the organs of sense, with which
animated beings are endowed, and the sensations
which are, in consequence, excited ; we
shall find, that although it is very true, that in
order for sensations to be produced, the agency
of external means on the sentient principle is
absolutely necessary ; it is, nevertheless, most
certain, that the sensation itself does not abide
in the external substance by which the impression
is made, but in the living and animated
being alone.
That this is the fact, will appear, if the effects
are examined, which are produced by the
same impressions on beings of different classes,
as well as on the same individual at different
times. It is very probable, that impressions
102 SENSATION AND ITS OBJECTS.
of the same kind, and of the same strength, induced
on animals of the same class, and of the
same age, excite, in them, sensations of the same
kinds. It is, however, certain, that very different
sensations are excited by the same impressions
on animals of different species: that
impressions which excite the sensation of pleasure
in some, will be found to give pain to
others ; and the same objects are known continually
to vary in the sensations which they
produce : the hands and fingers of the same
individual, under different circumstances, if
plunged into water of the same temperature,
shall, at one time, excite the sensation of heat,
at another time, of cold; the undulation of
the air, which at one time will be scarcely audible
to the ear, will* at another, appear like the
voice of thunder, and give the sensation of pain,
(as in pJirenitis.) In a state of health, the same
degree of illumination which excites the sensation
of pleasure in the eye, in opthalmia,
will occasion a color resembling a flame of
fire.
A cup of cold water, which generally
quenches thirst, and gratifies the palate, in a
state of health, if merely presented to a miserable
being laboring under hydrophobia, will excite
the most dreadful convulsions that can be
conceived, as well as the most unutterable
thirst, with foaming at the mouth ; and will
SENSATION AND ITS OBJECTS. 103
accelerate death by the most agonising means.
If the sensations which beings possess, were
inherent in the external substances, instead of
those sensations being multiplied and continued
without end, they would be limited and confined
to the particular instant when the impression
was conveyed ; and unless it were continually
repeated, the sensation could never be recalled.
Facts, such as these which I have stated, and
of which there are no end, decidedly ppove that
sensation does not abide in the external substance,
but in the living and animated being
alone ; they prove that the sensation of sweetness
does not abide in sugar, flavor in a rose,
cold in snow, or heat in lire, any more than
pain in a whip, or in a sword. These different
bodies constitute the agents only, by which impressions
on the nerves of sense are made.
Although, in common conversation, we are’
in the habit of connecting impression and sensation
together, as if subsisting in one, and the
same subject, nothing can be more incorrect:
instead of confounding the impression with the
sensation, the one ought to be separated from
the other. The question to be determined, is
not, whether the sensations inhere in these bodies
; we might, with as much propriety, seek for
the living among the dead, and ascribe to death
the efficient cause of life ; to immobility the cause
of motion to ignorance, ofdesign to fatuity, of
104 SENSATION AND ITS OBJECTS.
thought ; to necessity, of free agency as affirm,
that these sensations do actually inhere in
them; that heat is in fire, cold in snow, whiteness
in silver, blackness in jet, &c.
The proposition to be solved, is this ;
what are the bodies which possess the power of
conveying impressions to the organs of sense in
general, by means of which sensation is produced?
What are the bodies, which impressed upon the
eye, shall cause the sensation of illumination in
general, and of color in particular; upon the
ear, the sensation of sound in general, and of
tone in particular ; upon the tongue, taste in
general, and flavor in particular ; upon the
skin, feeling in general, the feeling of pleasure
or pain, of heat or of cold, in particular?
A proposition, such as this, may be solved
with as much certainty by a child of five years
of age, as by a man who has lived to the years
of Methuselah : a child will, at once, affirm
that strokes or impressions made on him by a
rod, give him pain ; that a rose is fragrant ; that
gold is yellow ; silver, white ; jet, black ; sugar,
sweet; vinegar, sour; fire, hot; snow, cold.
Not that these sensations actually inhere in
these bodies, but that these bodies, impressed
u^on the different senses, produce or excite
upon them different sensations, to which different
and appropriate names have been given ; of
SENSATION AND ITS OBJECTS. 105
illumination and variegation, of flavor and of
odor, of hot and of cold. Mr. LOCKE,* therefore,
makes a very just distinction between the
properties which essentially belong to different
bodies, and between those which exist in our
own perceptions :
” while the bulk, number,
figure, and motion of the parts of fire or snow
are really in them, whether our own senses
perceive them or not, and, therefore, may be
called real qualities, because they really exist
in those bodies. But light, heat, whiteness, or
coldness, are no more really in them, than sickness
or pain is in manna. Take away the sensation
of them ; let not the eyes see light, or
color, nor the ears hear sounds ; let the palate
not taste, nor the nose smell; and all colors,
tastes, odors, and sounds, as they are particular
ideas, vanish and cease, and are reduced to
their causes, i, e. bulk, figure, and motion of
parts.”
While each individual organ can only obtain
a partial knowledge of any subject ; the eye, of
color, the touch of resistance, the nose of flavor,
and the tongue of taste; the mind on the contrary,
which subsists not like the organs in
parts, but as a whole total and universal, re-
* Locke’s Essay on the Human Understanding, ch.
- 100.
106 SENSATION AND ITS OBJECTS. .
ceives the impressions wholly and totally, and
contemplates altogether, and at once, the various
attributes of the body, a perception of which
the organs of sense had separately obtained.
While the organs of sense, therefore, distinguish
the particular attributes of a body, the mind, on
the contrary, receives and conceives these per*
ceptions, universally ; things partible it views
impartibly; things divisible, indivisibly; things
temporal, eternally.*
Although the organs of sense are the avenues
through which impressions from external objects
are first made, it is from the native vigor
and power of the mind, that ideas are made to
flow ; while the spark comes from without, the
flame resides within ; although it is set in motion
by external means, it is from the power of
mind alone, by which those ideas and motions
ought to be directed.
Hoping that I have succeeded in showing
that sensation does not abide in the external
substance, but in the sentient principle alone,
* While the different attributes which the organs of sens*
perceive, constitute the true sources, whence definition ought
to be derived ; nomenclature, on the contrary, is made from
the congregation into one point, of all the attributes together.
The definition of silver or of gold, is not confined to its color
only, hot to its color and density ; its diagnosis from other
bodies consists in its malleability and relative weight, &c.
SENSATION ANI> ITS OBJECTS.
it will be easy to understand, that what is void
of thought and of reason cannot be the cause
of thought and of reason ; that although sensation,
any more than ratiocination, cannot exist
without an instrument or organ; the organ is
not the cause either of sensation or ratiocination
; although right thinking and feeling may
not take place without a right disposition of
body, a right disposition of body is not as a
consequence, the efficient cause of right thinking.
The body, it has been well observed by a
celebrated divine, may hinder thought, but
cannot effect it ; the faculties of the soul like
the sun, may be obscured and eclipsed by an
interposing body, but as soon as the obstruction
is removed, the light will shine out again in
full lustre.
What are the individual properties of which
the different bodies are composed, whieh, impressed
upon the organs of sense, excite the
different sensations, is a physical not a physio*
logical question, and is more cognisable by
the natural philosopher, than by the physiologist.
It is the province of the chemist to analyse the
materials of which the different kinds of food
are composed ; to ascertain the parts which
constitute the difference, by which one species
of food is, in its nature, different from the rest;
108 SENSATION AND ITS OBJECTS.
beef from venison, madeira from claret; to
ascertain what are the constituent materials
which, flowing from different bodies, excite on
the olfactory sense, flavors so various and opposite;
to ascertain the quality of bodies
through which impulses are propagated, and
which excite on the auditory nerves the sensation
of sound, or why a bed of roses and a
bed of thorns, excite the sensations of pleasure
and of pain ; to ascertain the nature of the
atmosphere in general, as well as of the different
bodies which excite upon the nerves of
sense, the sensation of dryness and of moisture,
of heat and of cold ; to separate the matter
which excites the sensation of heat and of cold,
from such as excites the sensation of color ;
to prove what fire is, as well as ice. It is the
duty of the chemist to analyse the materials,
which, flowing from different bodies, excite
upon the eye the sensation of illumination in
general, and of color in particular ; not only to
segregate a beam of light into rays, but to analyse
each ray into its constituent parts; to separate
the matter of color from the matter of
light; and finally, to present the solar ray pure
and unmixed, as it subsists in its elementary
and uncombined state. Until ready and most
satisfactory answrers can be given to these points,
I shall consider chemistry most defective and
SENSATION AND ITS OBJECTS. 109
imperfect, undeserving the name of science, and
merely ranking on a level with other arts.*
The sensation on the surface of the body is
excited by the resistance which is opposed to
the nerves situated under the skin, the nature
and the design of which depend on the peculiarity
in the arrangement of the particles of
the external substances ; it is from that peculiarity
that we decide whether a body be solid
or fluid, whether it be rough or smooth, blunt
or sharp. In the organs of hearing, sound in
general is excited by impressions on the auditory
nerves, through the medium of the tympanum
; and it is owing to the various undulations
of the air, modified and altered by the organisation
of the external fabric of the ear, that
sound in general, is made sound particular;
sound particular manifested by the variety of
tones, so distinctly perceived by those who have
what is called a good ear. In the organ of
hearing, sound may be considered the genus,
tones, the species.
In the organ of smelling, the sensation of
odor is excited by the particles of bodies which
* I purposely omit to notice the analysis of any part of the
living system, whether of animals or vegetables; because
chemical analysis of any portion of it, can only be accomplished
after death ; and, consequently, during the life of the system,
the excretions alone are the parts, in examining which the
chemifct may amuse himself.
110 SENSATION AND ITS OBJECTS.
are applied to the olfactory nerves, through th<
medium of the scneiderian membrane: odor iu
general, is the genus, the quality of those odors
the species, whether aromatic or fetid. In the
organs of taste, the sensation of flavor is excited
by the different substances more especially received
for food, and which are applied to the
nerves of the tongue ; while flavor in general,
constitutes the genus, the variety of sensations
which different kinds of food produce, constitutes
the species. In the organ of vision, the
rays of color impressed on the retina of the eye,
excite the sensation of illumination in general,
(and like different articles of food which excite
different flavors,) different bodies conveyed to
the eye, produce different colors. Every substance,
therefore, in nature, which exists, of
which the eye has any cognisance whatever,
whether it is black or white, brown or yellow ;
or, in short, whatever color it may assume, so
long as it exists, the sensation of ill animation
piust be considered to be colored.
Had physiologists and chemists been properly
informed of the distinction which exists between
impression and sensation between the
thing received and the receiver between the
substance without and the sensitive principle
within we should have been spared the pain
of hearing opinions promulgated and taught by
those few, very few individuals, who lay down
law, and who have been deluding the world
SENSATION AND ITS OBJECTS. Ill
&r some centuries past, down to the present
moment; we should have been spared the
folly of being called upon to believe opinions*
that are not more revolting to the feelings, than
they are to the good, common, unsophisticated
sense and apprehension of mankind.
Instead of supposing, that the coloring quality
of matter abides in the body whence it
flows, like every other quality which causes
impressions upon the other organs of sense, it
is absolutely affirmed, and universally believed,
that the color of a body proceeds from what
the body does not possess ; instead of arising
from rays of color which issue out of it, exciting
upon the optic sense particular sensations,
to which the names of particular colors have
been given ; it is supposed, that the color of every
body proceeds from rays of color which were
never admitted within it
; but that are repelled
from it ; and that a white body is ivhite, because
it reflects all the rays, but absorbs none ; and
a black body, black, because it absorbs all
the rays and reflects none ; it is, therefore, concluded
that neither black nor white are colors.
I would, however, ask any of these persons,
whether the matter by which the sensation of
white or of black is excited, is not as actual
and potential, as that by which the sensation of
red or of green, &c. and whether snow and jet
have not an actual existence, as certainly as
gold and indigo.
112 SENSATION AND TTS OBJECTS,
Instead of supposing that the quality of matter
by which the sensation of cold is produced
is as absolute as the quality of matter by which,
the sensation of heat is excited, it is, on the contrary,
universally affirmed and believed, that
cold is a negative, not a positive property.
During the winter season, when we behold
fluids converted into a solid form ; water become
ice ; vegetation suspended ; animation often
rendered torpid and destroyed by mortification;
although these effects are produced
by that modification of matter called cold, it
may, perhaps, appear somewhat strange to men
ofcommon feelings, who possess common sense,
that the actual existence of the matter which excites
cold, instead of being admitted, should be
denied by all the most enlightened chemists and
experimental philosophers, as they call themselves,
of the present day; and that none but
ignorant fools, if any there are so foolish, dare
to think otherwise. It is also maintained, that
the effects which are produced in the polar regions,
as well as in other countries during the
winter, do not proceed from the matter of cold,
but that they arise from the privation of heat ;
as if snow or ice applied to bodies in whjch
those effects take place, have not an actual existence,
as much as a flame of fire by the impressions
from which the sensation of heat is
etxcited, and combustion produced.
CHAPTER V
ON fHE PHYSIOLOGY OF ORGANIC LIFE,
AFTER having detailed, what I conceive to be
the deplorable state of ignorance which generally
prevails respecting the nature and power
of the principle of life, arid of mind, as well as
the relation which matter bears to them ; I shall
proceed to show that the same ignorance exists
respecting the functions of the different organs
of which the animated system is composed,
through the energy of which the various ends are
obtained, for which animated beings areespecially
designed. That the nerves are the organs of
sense, as the muscles are of motion, comprehends
all we know of their nature ; but of the
manner how impressions received, are conveyed
to the brain, in which the impression
ends and consciousness begins ; and how volition
and motion are imparted to the different
muscles of voluntary motion ; whether these
i
114 PHYSIOLOGY OF ORGANIC LIFE.
effects are accomplished tli rough the medium
of a subtle fluid which the nerves contain, as
Sir ISAAC NEWTON and others with great probability
of truth have asserted, or according to
the opinion of some, by vibrations excited
through nerves of a solid fabric, like thrills on
a brass wire, is not only a matter of hypothesis,
but is as unknown to the best physiologist, as
it is to the rudest barbarian.* With respect tothe
cause of motion, although the subject has
occupied the attention of many ingenious
and inquiring men, at different times ; we possess
tfo other knowledge of it, than that the
muscles are the agents by which motion is
produced ; but of the cause why, we continue
in the most profc aid ignorance.
.The ignorance, at present existing, of thr
functions which I have mentioned, are especially
extended to those of consciousness. Although
the brain is the organ in which coiir
* The horrid cruelties which continue to be practised by
the Galvanic fire, and other means, on the gciatic nerves of
frogs, rather favor the former hypothesis; the experiment
once made, has ascertained all that ran be known from it, and
the fact might, therefore, be mentioned, but certainly ought
not to be repeated (as it is so often done) in order to produce
a Sort of stage effect, and to gratify ignorant curiosity. Little
did LORD BACON suppose, that the system ofinduction which
.he introduced, would have been converted into a system of
.torturf.
PHYSIOLOGY OF ORGANIC LIFE. 115
Iciousness resides, \ve are totally ignorant of
the manner by which its actions are displayed ;
how it is, that without being muscular in its
fabric, it is, nevertheless, the cause of muscular
motion ; how, though formed of parts which
were originally destitute of sense and of reason,
it, nevertheless, constitutes the instrument from
which the principles of sense and of reason
perpetually flow. Notwithstanding all analogy
justifies the opinion that the brain is an organ of
secretion, the fact has never been demonstrated,
and the most perfect ignorance exists, at this
time, how, this most important organ of the
whole system acts, and what is its nature.
This state of ignorance has been very candidly
confessed by Sir Busic HARWOOD, the present
learned and respectable professor of anatomy
at the university of Cambridge :
” When we
dissect the brain,” says he,
” and observe the
different substances of which it is composed,
and their different forms ; imagination, assuming
the office of reason, would willingly assign
a peculiar use to every part, and pronounce
one to be the residence, or rather the instrument
of memory; another of abstraction, a third of
volition, &c. When a sensation is excited by
the action of any substance upon the body, we
immediately perceive upon what part of the
body, the substance acts, where the impression
begins ; and as the impression is conveyed by
I 2
116 PHYSIOLOGY OF ORGANIC LIFE.
the nerves lo the brain, it is conceivable that
we might be so constituted as to perceive, with
the same facility, in what part of the brain the
impression ends. This, however, experience
convinces us, we are not able to determine.
The skill of the anatomist has demonstrated
every process, explored every cavity, and
would, if possible, have traced every filament
of this inexplicable mass, of that wonderful and
anomalous organ placed on the doubtful confines
of the material and spiritual worlds ! nor
have the physiologist or metaphysician been
less eager to discover or to assign to each part
its peculiar office ; whatever may be due to the
former for accuracy, and to the latter for ingenuity
and zeal, we must lament that little knowledge
has resulted from their labours. At this
advanced period of science, when almost every
subject has been illuminated by the experiments,
the deductions, and even by the conjectures
of the learned, we are not able to proceed
a single step beyond the fathers of medicine,
xvho, in the very infancy of our art, pronounced
this inscrutable mass of organised matter to be
the fountain and the reservoir, the beginning
and the end of the whole nervous system, where
every idea originates, and to which every sensation
is referred.”
Having investigated the subject of fecundation,
the result of which 1 have detailed at
PHYSIOLOGY OF ORGANIC LIFE. 117
large in my PHYSIOLOGY, as well as in two
papers published in the MEDICAL JOURNAL for
the year 1799, I shall merely observe in this
place, that the object which I had principally
in view, was to show, that the ideas entertained
on it by Dr. HAIGHTON, and which have been
published in the PHILOSOPHICAL TRANSACTIONS,
were altogether erroneous ; that he had
discarded and rejected all analogy whatever,
and the evidence which is furnished to ns by
vegetables, by fish, and by the amphibia, as
well as by other classes of animals. Instead of
taking the actual existence of a foetus, as constituting
the only infallible test of animal impregnation,
he assumed the formation of a corpus luteum
in the ovariurn for the evidence of it. I proved
that the very facts which he had advanced were
decisive in showing he had proceeded from
false assumptions ; that in all those cases in
which he divided the fallopian tube of one side,
and left the one on the opposite side, perfect
and undivided, although there were corpora
ititea in both ovaria, there were foetuses only in
the perfect, but no traces whatever of a foetus
in the mutilated side; that although oestrum
had produced an evolution of the ova in both
oraria, impregnation was apparent only in the
perfect one. Notwithstanding these facts which
he himself had obtained, he concluded that the
existence of corpora, In tea was the test of im118
PHYSIOLOGY OF ORGANIC LIFE,
pregnation; and from this false fact and false
assumption, he has proceeded to investigate the
subject, and to make from them the most erroneous
qonclusions. He might, with as much
propriety, have supposed that the ova of birds
which we see continually dropped from the
ovarium without impregnation, are actually impregnated,
or that the corpus luteum, which
is in consequence formed, is the test of it ; although
certain evidence existed that no union
between the pairs had taken place, and where
corpora lutea had been formed, but no impregnation
whatever.
So little is known, at this time, of the nature .
of Hood, that with few exceptions, the generality
of physiologists absolutely deny to it the
attribute of vitality. They deny the attribute
of vitality to that important matter, from which
every part of the living system is formed; which
supplies the wants, and which restores the
waste that different parts suffer. Mr. J. BELL,
who must be considered as high authority in
this matter, calls the vitality of the blood ” the
most monstrous of all absurdities.” The vita*
lity of the blood is an opinion almost as antient
as the Mosaic account of the creation. The
sacred writings tell us, that ” the life is in the
blood,” that is to say, that the life of the animal
or of the vegetable is in the blood, in common
with the other parts of the body ; not separate
PHYSIOLOGY OF ORGANIC LIVE. 119
distinct from it, but co-existing and connate
with it. That the blood is alive, was considered
by SERVETUS, two hundred and fifty years ago,
(it made one of the charges preferred against
him before he was brought to the stake), a
well as by onr illustrious countrymen HERVEY.
and HUNTER. It is greatly to be deplored, for
the cause of science, that Mr. Hunter’s active
and comprehensive mind should have been
destitute of those collateral branches of knowledge
which are intimately connected with the
science of physiology : he saw truth, but he
saw it at an unapproachable distance, he saw
it in a fog, he saw7 it through a glass darkly.
Although Mr. Hunter revived the exploded
doctrine of the vitality of the blood, he nevertheless
supposed that this vitality was, as it
were, separated from the other parts of the system
; that the blood had a life, sui generis, or
as he termed it, that the blood was an animal
within an animal ; imperium in imperio ; that
it possessed a sort of animation or power of ac
tion within itself, similar to muscular contrac
tion ; that it was by virtue of this power, that
bones were formed and renewed, and the various
processes of secretion and of growth
carried on ; that, in fact, all the phenomena
which are produced by it proceeded from powers
inherent in it.
These false assumptions grubbed up the road
120 PHYSIOLOGY OF ORGANIC LIFE.
which he himself had paved, of discovering the
relation which the blood bears to the organs ;
and at once blasted the fair prospect which he
had opened to our view, of seeing the nature
and design of secretion ; instead of which the
process of secretion, so important and extensive
in the living system, is acknowledged by
all to be involved in utter darkness.
Our ignorance of secretion appears to me, in
a great measure, to arise from mistaking the
relation which the blood bears to the organs by
the energy of which it is acted upon and chang-r
ed ; instead of considering blood as the passive
recipient, as thesubject matter to be acted upon,
not only by the vessel in which it is contained,
but by the organ in which it is deposited ; it is to
the stimulus of the blood, more than to its aptitude
to be acted upon by the organs of secretion,
that the changes which it undergoes are referred.
The relation which subsists between the matter
from without, and the digestive organs
within, is precisely the same, in kind, as that
which subsists between the blood and the vari^
ous parts to which it is conveyed. While the
digestive organs unify and assimilate different
species of matter to one, and the same kind, and
which afterwards subsists in the form of blood ;
the different secretory organs, on the contrary,
have the power to convert this blood into fluids
and solids, in their nature totally different ; as
PHYSIOLOGY OF ORGANIC LIFE. 121
we behold in the various secreted fluids that are
produced from the blood of the same animal
and the medulla of the same plant. Blood
bears the same relation to the power which the
organs severally possess, as brick and mortar
do, to the architect or to the artist, by whom a
building is erected. It has no more the power
to convert itself into organisation or form, than
brick and mortar have, of themselves, the power
to erect a building. If it possessed any power
of action within itself, by virtue of the sen*
sible properties it contains, it would resist the
action of the organs to which it was applied,
it would act upon them, instead of being changed
and converted by them : if it had the power
of converting itself, by itself, either into different
organs or into different fluids, the previous
existence of those organs would be unnecessary,
since the process of conversion and of secretioji
would take place without their influence. We
might as well suppose, that a building can be
erected without hands, and designed without a
designer; an effect produced without a producing
cause; or, what is equally absurd and
false, that the effect and the cause are inherent
in one and the same subject.
By virtue of its passivity, the capacity of
blood arises not only of being moved, but of
being changed and organised ; it has the capacity
of being moved without having any power
122 PHYSIOLOGY OF ORGANIC: LIFE.
of moving itself; following, without resisting,
the impulse it receives from the vessels in which
it is contained. It has the capacity of being
changed by the power of the part in. which it is
deposited ; yielding without resisting, as the
softened and adapted wax to the force of the
impression engraven on a seal. It bears the
same relation to the secretory organs, as air
does to the organs of sound ; if the air expired
from the kings, inherently possessed any particular
sound, that particular sound would constantly
manifest itself; but air being destitute
of all sound, retains the capacity alone of being
expanded and compressed ; it thereby becomes
fitted to be acted upon by the organs of speech,
and through their power it is modulated and
harmonised, arid language ultimately produced.
It is with a view of preserving this aptitude
in the blood of animals, and of preventing the
sensible qualities which the coarser parts contain,
from being employed; or exerting any influence
upon the organs ; that we behold the
design and end for the exhalent termination of
arteries in capillary tubes ; by means of which
a mechanical cause exists to prevent a mechanical
and deleterious effect. If it were not for this
mode of construction ; if the terminated diameter
of the exhalent arteries w^ere large instead of
small, not only the more tenuous, but the more
globular parts of the blood wrould be permitted
PHYSIOLOGY OF ORGANIC LIFE. 123
to flow through ; those parts of the whole would
flow through, which possess quantity with
color and figure; quality without aptitude;
that would act upon the organs instead of retaining
the fitness alone to be acted upon by
them. To prevent this evil, a gradual diminution
in the size of the secretory vessels exists,
in order that the fluid which they exhale may
answer, in the best possible manner, the end for
which it is designed; this fluid is, therefore,
tasteless and inodorous, colorless and tenuous.
If blood possessed any power of action within
itself, it would resist the action of the organs
to which it was applied ; it would act upon
them, instead of being changed and converted
l)y them ; it is moved without the power of
moving itself; it is propelled without resisting,
and follows the impulse it receives, from the
power of the vessels in which it is contained ;
not according to the principles by which fluids
are moved in hydraulic machines, but by powers
altogether different from them. The relation
which exists between the blood and the vessel
in which it is contained, is precisely the same,
in kind, as subsists between the glands on which
it is deposited, and the blood : while the power
of the one is similar to the figures engraven
on a seal, the other resembles the softened
and adapted wax which is to receive the impression.
It is by the energy of the former, and
124 PHYSIOLOGY OF ORGANIC LIFE.
aptitude in the latter, that the various processes
of secretion and nutrition are carried on. Instead,
however, of supposing that the changes
which are produced on the blood, arise from
the agency of the glands, or of the part in which
it is deposited ; the change, for the most part, is
referred to the; power of the blood upon the
gland ; the act is stated to be a chemical, rather
than a living one ; and the aggregating principles
of physiology have been abandoned to the
decomposing powers of chemistry. Every solid
and every fluid have in consequence been
analysed with the utmost accuracy, and from
bodies, whose elements were found to be the
ame, effects which are altogether different,
are attempted to be explained.
If I proceed to detail the opinions which areentertained
respecting the function of the organs
which subserve the office of meliorating
the blood from the deterioration which it constantly
sustains, they will be found most erroneous
and contradictory. Instead of considering
the lungs, (as I conceive they ought to be
considered,) as much organs of digestion as the
stomach itself, the one acting upon, and digesting
particular kinds of air, as much as the other
is known to do particular kinds of food ; that
while the latter restores the waste which the
blood sustains in point of quantity, the former
meliorates it in point of quality; and, by the
PHYSIOLOGY OF ORGANIC LIFE. 125
iinited power of both, it is preserved in a state
fitted to answer the ends for which it is designed
; instead, however, of supposing that
the lungs act upon the air, it is supposed that
it is the air which acts upon the lungs, and,
like the action of the food upon the stomach,
that it is a chemical, not a living act.
Instead of separating the function of respiration
in general, as it ought to” be, into inspiration
by which air is received into the lungs into
digestion, by which particular portions of it are
separated from the rest, and received into the
blood for its melioration and support ; and,
finally, into expiration, by which the residuary
and feculent parts are expelled from the system:
the process of respiration, on the contrary,
is confined to inspiration and expiration
only. I shall not dwell upon the multitude of
cruel experiments, which have been made on
cats and dogs, in order to ascertain the quality
of the different materials which are received
and expelled : in spite of all the means which
bave been employed, these chemical physiologists
continue at variance, and have not yet
settled whether oxygen air, or caloric, is obsorbed.
The late experiments made, without
the aid of torture, by two eminent chemists,
MESSRS. ALLEN and PEPYS, upon this subject,
would seem to disprove all the experiments
that have been made before : they go to show
126 PHYSIOLOGY OF ORGANIC LIFE.
that although much carbonic air is expired,
little or nothing- is taken in ; however high the
authority certainly is, whence this opinion
has come, I, nevertheless, consider the actual
change of color, and of consistence, from black
and thick, to red and liquid, which the blood
undergoes as it passes from the heart through
the pulmonary artery, and through the lungs
to the pulmonary veins, is far more decisive
than any chemical experiments performed on
the air out of the body can disprove ; that independently
of what is expelled, a considerable
quantity of matter is, nevertheless, received,
the quality of which it is not worth a
rush to ascertain ; the experiments made by
Mr. HUNTER, Dr. GOODWIN, &c &c. are decisive
on this point.
Equally at variance, are physiologists, with
respect to the manner in which the matter acted
upon by the lungs is conveyed ‘into the blood.
Instead of supposing that the parts of the air
which have been separated from the whole, are
absorbed by the extremity of the pulmonary
veins, as the nutritious matter which the placenta
furnishes for the support of the foetus is
unquestionably absorbed by the extremities of
the umbilical veins, or as the chyle by the
chylous (lacteal) vessels : it is generally supposed
that the air forces its way into the blood
by the most unnatural means ; not through the
PHYSIOLOGY OF ORGANIC LIFE. 127
medium of open orifices which are greedy to
receive it, but through the solid and impenetrable
sides of the vessels themselves. A construction
of vessels which would permit the
access of air through, would evidently admit
the egress of it also. The assertion has been
disproved by experiments which were made to
support this opinion. The jugular vein of rabbits
has been exposed, and oxygen air by
means of a blowpipe, has been directed upon
it, without producing any sensible alteration
on the blood that flowred through it; on removing,
however, the external coat of the vessel,
it was supposed that the color of the blood
then underwent some change, and became
more florid than before: a false fact such as
this, will not, I trust, give any weight to such
an opinion, more especially when we reflect
that the actual and palpable existence of air in
the blood, is immediately attended with convulsions,
and with death. It is the mode which
many farriers now adopt to kill horses. By
means of a blowpipe they introduce a small
quantity of air into the jugular vein, which, after
a few struggles, puts an end to the animal’s
existence.
Although chemical physiologists have been
undecided with respect to the quality of the
matter which has been received from the lungs
into the blood, they have been, generally speak1S8
PHYSIOLOGY OF ORGANIC LIFE.
ing, unanimous m opinion, that it was the
source and the cause of animal heat, ff such
an hypothesis were true, it must, as a consequence,
follow, that the temperature of the
blood must be higher at the point near which it
is received* than in the most remote parts from
if
; find that the blood on the left side of the
heart ought, in that case, to be hotter than the
blood on the right side of it. The fact, however,
is precisely the reverse. The experiments
made by Mr. A. COOPER, (and there is
no man more able, or more to be depended
upon,) show, in a manner the most decisive,
that the blood on the right side of the heart, at
the greatest possible distance whence the matter
of heat is supposed to be received, was from
two to three degrees hotter than the blood on
the left side, the nearest point to the supposed
source of heat. If the hypothesis, therefore, is
admitted to be true, we must also admit the
absurdity, that a body is heated to a greater
degree when situated at a great distance from
a fire, than when it is placed close to it.
How the gaseous matter received from the
lungs, acts upon the blood, except by changing
its color and consistency, is as unknown at
present, as the operation of medicine upon the
stomach. The causa operandi of medicine ip
altogether unknown, and the modus operandi is
only acquired by experience, obtained through
PHVSIOLOGY OP ORGANIC LlFE. 129
the medium of observation, and of accident.
The best physician existing can no more tell
the cause why tartarised antimony has an emetic,
or the sulphate of magnesia, a cathartic
effect, than the most ignorant nurse living 5
much less, (if total ignorance would admit of
degrees,) how specific remedies produce specific
effects, in curing particular complaints.
Let it not, therefore, be arrogantly asserted,
that there is any science in pathology, or in
the practice of medicine ; it is absolute
quackery.*
The ignorance which exists respecting the
actual functions of the organs which meliorate
the blood in point of quality* extends to those
* I wish, however, to be clearly understood ; I speak of the
practice of medicine as a science, not as an art . The observations
and experience of intelligent and sensible men have been
the means of employing the different remedies to the greatest
advantage, which relieve and cure different complaints ; and,
the man who has the greatest experience, and who has the best
capacity to make observation on the progress of the different
symptoms of the same disease, and to compare different diseases
with each other, is, unquestionably, the man who is most
likely to constitute the best physician. With respect to surgery,
there is, perhaps, no branch ofart that has undergone,
within the last thirty years, greater improvements, not only
as to the instruments employed, but also in the mode of
using them ; and the sufferings of mankind have, in consequence,
been greatly mitigated ; these observations may, i
some degree, be applied to the obstetric art also.
K
130 PHYSIOLOGY OF ORGANIC LIFE.
which supply the waste it sustains in point of
quantity also.
With respect to saliva, instead of considering
it as an auxiliary to the teeth, in acting upon
the food ; it is, for the most part, viewed as a
mere mucous fluid, intended to lubricate the
surface of the mouth. The saliva, however,
seems destined to a higher office. While the food
is broken down, with respect to mass, by the mechanical
action of the teeth, the saliva is intended
to assist the teeth in comminuting those parts
into smaller particles. It is one of the first
agents employed to eliminate the specific and
chemical qualities which the food contains ; it
bereaves acids of their acidity; alkalies of their
acrimony ; and, to a certain and limited extent,
blunts the asperity of both; rendering the
different articles of food bland and mild, as a
preparatory step to the action, in the stomach,
which the food is to undergo.
The various facts which were produced by
Mr. HUNTER, and which have been multiplied
without end, by others, prove, in a manner the
most decisive, that the change which the food
undergoes in the stomach, from a dead to a
living state, is a living, not a chemical act. Although
all agree that the gastric juice is the
agent, by the energy of which the process is
accomplished, with the exception of a few, the
effect is referred to a chemical, not to a living
PHYSIOlOGY OF ORGANIC LIFE. 131
cause. With as much rationality might we
refer to death, the cause of life ; to organic
action, the source of organisation ; or assert
that the feculent matter in the rectum, is the
seat of chylification. It is scarcely necessary
for me to expatiate on the folly of these opinions.
They tend to revive the exploded doctrine
of M’BRiDE, that digestion is a process of
fermentation and putrefaction, and that the
same means are employed, in the animated
system, to bring dead matter into a living state,
as are employed to decompose and reduce
living matter, to one dead arid common. The
gastric juice, like the other fluids, has been analysed
also, but instead of manifesting any chemical
properties to which its power can be referred,
it has been found to be destitute of
them ; it is neither acid nor alkalescent, but
perfectly insipid and inoffensive. Is it, I would
ask, reasonable to assert that a fluid such as
this, which appears to be destitute of all chemical
quality whatever, nevertheless acts by
chemical power ?
The same errors exist respecting the agency
of the means, by which a separation of the chylous
from the feculent parts of the chyme is
effected, after it has passed from the stomach
into the intestinal canal ; although the first portion
of the canal is evidently constructed with a
view to retard the passage of the chyme through
K 2
132 PHYSIOLOGY OF ORGANIC LIFE.
it, it is generally believed that the bile which
the liver secretes, is merely intended to accelerate
its expulsion/ It is far otherwise ; the
internal surface of the canal is increased, to a
very considerable extent, by means of a number
of ridges, or folds, which, at first, are nearly
concentric to each other, but which gradually
acquire a diagonal direction. Since, then, the
alimentary canal is constructed with a view to
retard the motion of the food through the first
part of its course it is most unreasonable to
suppose, that the real and direct intention of
the hepatic system, is to hasten its expulsion.
If this were the case, instead of harmony,
there would be perpetual warfare between
both : the retarding construction of the intestines
would always tend to prevent, what the
bile was designed to accelerate, and the ductus
communis, in such a case, instead of having its
orifice in the duodenum, ought to have it in the
rectum. Those who can reconcile this warfare
of parts that are dependent upon each other,
have very inadequate notions of the symmetry
that pervades the whole of the system, and of
the harmony that exists between the parts of
which it is composed. So far from supposing
that the primary use of bile is intended to defeat
the end for which the intestinal, (or the
chylous canal, as it ought more properly to be
called,) is so peculiarly constructed ; I think it
PHYSIOLOGY OF ORGANIC LIFE. 133
far more reasonable to conclude, that it is intended
to harmonise with it; and that the bile
instead of acting by its resin, and its alkali, as
an active purgative, is intended, in the first instance,
to separate the chylous, from the feculent
parts of the chyme ; producing a precipitation
of the one, and afterwards assists the
expulsion of the other, conformably to experiments
which have been made to ascertain
the point.
With respect to the pancreas, or sweetbread,
although it secretes a fluid of a quality bland
and mild, somewhat similar in its prpperties to
saliva, and which, probably, co-operates in accomplishing
the same purpose as the bile from
the liver ; the specific determinate use to which
this fluid subserves, continues, to the best experimentalist,
a perfect mystery.
The same uncertainty prevails respecting
the use of the spleen. The well-known fact,
that it has been altogether absent in animals
which, in general, have one; and that it has
been extirpated without producing any violent
shock to the Constitution, led to the supposition
that it was of little or no use. Dr. STUKELEY,
seventy years ago, in his Gulstonian Lecture,
traced the connexion which subsists between
the spleen and the stomach, as well as
between the other abdominal viscera ; and, from
a very scientific mode of investigation, was led
134 PHYSIOLOGY OF ORGANIC LIFE.
to conclude, that the spleen was designed to
assist the stomach in the process of digestion.
These opinions of Dr. STUKELEY, have since received
some confirmation from experiments made
by Dr. HAIGHTON, the respectable lecturer on
physiology, at Guy’s Hospital. The Doctor was
led to conclude, that when the stomach was distended
and full, the pressure which the spleen
is made, in consequence, to undergo, not only
prevents the passage of the blood through that
organ, but that it actually does produce an increased
accumulation, in the vessels with which
the stomach, and the pancreas, are supplied.
Greatly as I respect Dr. HAKJHTON’S talents
and industry, there are many objections to his
experiments upon this subject ; and, the fact
that, in some animals, the situation of the stomach
and the spleen are so remote that they
cannot come in contact, may probably appear
an insuperable objection to his hypothesis.
Mr. HOME, who holds the first rank in his profession,
and who must be considered very high
authority also, from different experiments which
he made on dogs, is of opinion, that the food
from the stomach undergoes some change in
the spleen, not through the medium of the absorbent
vessels, but by some unknown mode
of communication. After tying the pyloric extremity
of the stomach, and injecting into that
organ, infusions of madder and of rhubarb,
PHYSIOLOGY OF ORGANIC LIFE. 135
and killing the animal, he found that the cells
of the spleen, (particularly at the great end of
it,) were very large and distinct ; on macerating
a portion of it in ten drachms of water, and
testing it by an alkali, he found that it gave out
a reddish-brown color in the centre, and no
where else. A similar portion of the liver was
treated in the same manner, and an alkali was
added to the strained liquor, but no such
change in it was produced. I mention these
opinions in order to show how little is known
upon the subject.
The same confusion exists with respect to
the lacteal (or chylous) vessels ; those vessels
which arising with open mouths from the folds
of the intestines, absorb the chyle, or digested
aliment, after it has been depurated from its
feculent portions, and convey it to the mass of
blood, in order that the waste which it undergoes,
may be restored. The mode by which
the absorption is accomplished continues an
object of disputation; instead of supposing
that it is performed by a living power in the
parts, analogous to the suction of a leech, or even
of an infant at the breast ; by many it is considered,
an inanimate act, similar to the raising
different fluids in narrow tubes, by what is
called capillary attraction, Although the lacteal
(chylous) resemble the lymphatic vessels,
in the office of absorption, the substances on
136 PHYSIOLOGY OF ORGANIC LIFE.
which they act, are, in their nature, totally
different. While the former convey to the
blood the nutritious matter which the stomach
had assimilated; the latter, on the contrary,
are designed to remove and carry away those
pprts of the system which are worn out, and
which exisj; in a perishing and dying state ;
the former may be compared to cooks, who
constantly afford to the blood a supply, the
other to scavengers, who take away the dilapidated
parts of the system.
It is in obedience to the diversity in the end
to which each system is subservient, that there
exists a diversity of power between them at
(different periods of life ;
i infancy and youth,
while the system is in a state of progression
jin4 growth, the lacteals are large, and the
lymphatics comparatively small. At the middle
periods of life, when the system has attained
the acme of perfection, both systems are, as it
were, balanced ; in old age, on the contrary,
when emaciation and decrease take place, the
balance between them is altogether overturned,
aiicl both scales are put into one ; the lacteals
become weaker and smaller, while the lymphatics
increase in magnitude and strength. IncJ
of contemplating the action of these ves-
, with relation to the separate functions
which they are designed to perform, both are
generally confounded together; while the fpiv
PHYSIOLOGY OF ORGANIC LIFE. 137
nier carry materiaTs to the blood, to supply the
waste which it suffers the latter receive from
the system the parts which are wasted, or
which have accomplished the purpose for
which they were enlarged. In no organ is this
office more striking, than in the uterus. Before
gestation, the lymphatics of that organ are remarkably
small and thready ; after parturition,
they immediately increase in size, and have
often been seen as large as the quill of a
goose : it is through their agency that the different
parts of the system, that are either super^
fluons, or diseased, are removed ; diminishing
the fabric of the whole by the parts which they
absorb, and often destroying the form itself.
Notwithstanding these avowed purposes for
which the lymphatics are designed, the opinion
which was first broached by Mr. HUNTER,
soon after they were discovered, that they were
the modellers of our frame, continues to be preserved.
Instead ofbeing modellers, they form the
agents only,*
1
by which the dilapidation of the system
is accomplished. If the power of these ves-
* The pig which had remained under the ruins of the cliff
which fell in at Dover, for the period of five months, was reduced
in weight, by the activity of these vessels, for the most
part, from eight score, to thirty-six pounds ; that is, he had
lost in weight 124 pounds.
138 PHYSIOLOGY OF ORGANIC LIFE.
sels, at the first periods of life, were equal to
those of the chylous, and secretory, the system
would remain stationary in infancy, as it
does at the period of manhood, without ever
arriving at it ; and, on the contrary, if the actions
of these vessels were not greater in old
age, than in infancy and manhood, there would
scarcely be in the system any diminution in its
size ; the whole would be like an evergreen, never,
perhaps, liable to perish or decay. But,
alas ! this period of decay does arrive ; it is
brought on by the loss of balance, between the
vessels subservient to the growth, and to the
decrease of the system. In the common course
of nature, the change is gradual and imperceptible,
but it, nevertheless, is constant and uninterrupted.
The arteries, with relation to the
veins, are small in size ; and the veins, on the
contrary, are large with relation to the arteries
; all, all is waste, and no supply : the
power whick the different organs originally
possessed, of imparting any vital energy to the
different substances that are applied to them,
and even of retaining their own, becomes lost,
and a total abolition of all sense and sensation,
of all consciousness and voluntary motion,
ensues. The different muscles, volun.
tary involuntary and mixed, whose actions depended
on the energy they ought to receive
from the matter contained within the cavity
PHYSIOLOGY OF ORGANIC LIFE. 139
of the spine and cranium, cease to act; and the
whole of the system becomes in the most perfect
state of paralysis that can be conceived, or
described; and that condition of the system is
induced, which is known under the appellation
of death.
It is not, however, the mere separation of
the fruit from the tree on which it grew; or,
the mere division of the orange, or the apple,
into parts, which constitutes death ; although
this separation diminishes, it does not destroy
its living and preservative property ; the
living property of different parts of animals,
is proved to exist for some time after they
have been separated from the system, to which
they belonged ;
it is proved to exist in teeth,
from the success which attends their transplantation
; in the blood, by its transfusion from
one animal to another; and in eggs, by their
evolution. The heart of a turtle, or of a frog,
will retain its irritability, and power of contraction,
for several days after it has been completely
torn out of the system, to which it belonged.
The whole external surface of the
animal is often frozen nearly to a state of petrifaction,
and, nevertheless, continues to
retain its preservative and living powers.
Under various circumstances, the different
organs are found to recover their particular
organic actions, as the vernal season advances ;
140 PHYSIOLOGY OF ORGANIC LIFE.
and the whole animal becomes as vivacious as
before.
If we are to credit the accounts published by
the HUMANE SOCIETY, organic action has been
resuscitated after it has been suspended for many
hours, and while the following torpid state was
present, the rigid limb the clay-cold skin
the silent pulse the breathless lip- the livid
cheek the fallen jaw the pinched nostril
the fixed and glassy $ye. CELSUS, and other
venerable authors, have recorded various instances,
in which organic action had been recovered,
after it had been suspended for several
days. Without trusting to human testimony
alone, we have also that which is divine; I
mean only what respects the distinction which
exists between apparent, and absolute, death ;
the recovery of action in all the cases related,
was miraculous effected by the almighty power
alone of the great Author of our salvation.
I might state the case of Jairus’s daughter,
mentioned by ST. LUKE. She was twelve years
old when Jairus first applied to Jesus :
” she
lay a dying:” but soon after she was so dead,
that the ruler of the synagogue told him,
” not
to trouble his Master:” all, therefore, wept and
bewailed her ; but, Jesus said,
”
Weep not, she
is not dead but sleepeth” They laughed him to
scorn, knowing that she was dead : and he put
them all out, and took her by the hand, saying,
PHYSIOLOGY OF ORGANIC L1F&. J41
” Maid arise;’ and her spirit came again, and
she arose straightway. Here then was a case
of suspension of all organic action, while the
power of preservation subsisted. We have
similar instances related in the book of Kings,
of the prophet Elijah reviving the widow’s son;
and of our Lord himself, when he reanimated
the son of Nain’s widow. On the contrary,
when the evangelist speaks of death, he makes
a very evident distinction between the signs
by which it is characterised, and those that attend
suspended animation only; as in the case of
Lazarus, who had been dead four days, where it
is said,
” that he stinketh” Here then we find, in
scripture itself, an evident distinction between
the mere suspension of organic action, while
the general properties of preservation continue
to subsist, and the total deprivation of life,
with the consequent loss of all organic power.
Death, therefore, constitutes that intermediate
state which exists, when the powers of life
are displayed in organic action, and the total
decomposition of the whole machine into its
constituent parts. However different the means
may be, by which death and decompostion are
effected, the end is certainly the same in
all. There are, it is true, various means by
which the actions of life are supported, as well
as various means, by which those actions can
be suspended, and annihilated. Every indivi142
PHYSIOLOGY OF ORGANIC LIFE,
dual system, however, has one life only, not
many lives ; so one living system can have one
death only, not many deaths ; however different
the modes may be by which that death may
be endured. Varied and prolonged as it may
be in mode and in time, it is the fate allotted
to all generated beings ; and to which they
are doomed : -they are essentially transient
and frail, and subsist in a constant state of
progression, perfection, decomposition, and
decay.
Putrefaction and fermentation are the means
by which the bond of animal and vegetable
matter becomes loosened, and broken ; and the
whole of the system develated from an organised,
to a disorganised state; the parts
that were fixed become volatile ; such as
were inodorous, become offensive to the olfactory
sense ; such as were insipid, become
sapid ; those that were homogeneous, become
heterogeneous ; and, finally, resolved back
from a dead, to a common state. Putrefaction
and fermentation, in fact, have the same relation
to dissolution, that the act of digestion has
to life ; while the act of digestion prepares
common and inanimate matter, and fits it to
receive the energy of the living principle to
which it is applied; putrefaction and fermentation,
on the contrary, bring back dead
matter to a common state : it is the last and
PHYSIOLOGY OF ORGANIC LIFE. 143
ultimate change, which it sus-tains, and which
alone virtually, and in fact, constitutes dissolutionnot
a suspension of organic action only,
but a total decomposition from its former state
of union.
The flesh and blood of a horse, or of an
ass ; of a monkey, or of a man ; of a materialist,
or of a philosopher, will yield the
same materials by decomposition. There may,
perhaps, be a greater quantity of ammonia in
the one, than in the other ; but as this difference
is frequently found to exist in the analysis
of the flesh of different men, no inference from
thence can be drawn, that the animal matter of
which these different beings are composed, is essentially
different. Decomposition is, therefore,
the last change they sustain, in order to reduce
the different parts from a living to a dead state,
that they may be ultimately converted into a
common one. The chair on which I sit the
paper on which I write and the pen with
which I am writing, in common with the
organic remains of the animal and vegetable
kingdom as well as the exuvise of both, constitute
dead matter.
After having stated what I conceive dead
matter actually to be ; to understand what it
is not, must be most obvious. Dead matter
forms no part whatever of the organs which
subserve to the functions of animals, or of ve144
PHYSIOLOGY OF ORGANIC LIFE.
getables ;
it neither exists in bones, or iti
muscles ; in blood, or in the different vessels ;
in the organs, or in the fluids which they
secrete, to answer a living purpose. Neither does
dead matter exist in any part of the elementary,
or common matter, of which the universe is
composed : it does not exist in solid or liquid
matter ; not in earth, or in water ; in fire, or
in snow ; in air, or in light so long as these
bodies subsist in a common state ; neither are
these bodies susceptible of undergoing the
spontaneous decomposition which dead matter
suffers.
It is by tracing the system of nature, from
animated beings, to such as are inanimate ;
from the agent, to the patient ; from the cause
to the infinity of its effects ; from things composite,
to things simple ; that we are enabled
ultimately to arrive, at the contemplation of
that primary elementary matter, of which the
whole of the universe is composed and filled.
Mr. HARRIS, the learned author of Hermes,
very accurately defines this matter, to be
that elementary constituent in composite substances,
which appertains, in common, to
them all, without distinguishing those composite
substances from one another ; for, although
the matter of which the ark, and the
ship the anvil and the saw, are formed,
may be, in kind, severally the same, and apPHYSIOLOGY
OF ORGANIC LIFE. 146
pertain, in common, to them all ; it, nevertheless,
does not distinguish the one from the
other. The one is distinguished from the
other, by the energy of the formative power
which converts matter, the same in kind, into
instruments totally different, this power does
not reside in the matter which is employed,
it proceeds, in them, from the efficacy of the
artist, by which the matter was modelled, and
from the power of the living principle by which
it was organised. It is this condition of matter
to which Mr. HARRIS has given the appellation
of primary matter the v^\ w^ul* of the
antients ; the substratum of which all composite
substances ar.e constituted, without in>
parting to them any distinguishing character
whatever. Common matter, therefore, with
relation to vitality, appears to be divisible and
penetrable in all its parts imbecil and inert:
to subsist, in fact, in a state of universal privation,
extension alone exeepted.
CHAPTER VII.
ON THE ELEMENTARY PROPERTIES OF COMMON
MATTER IN GENERAL.
SECTION I.
On the Matter of Light.
AFTER having detailed the state of deprivation
in which matter, in general, exists, with relation
to the principle of vitality, and the properties
which it has acquired through its energy it
will be easy to comprehend the nature of its
existence, after it has lost the participation of
Jife which it had received, and when it has
been finally and completely resolved back to
its common and elementary state, whether of a
fluid, or of a solid kind. Instead of contemplating
the nature of extension, and of bulk,
which matter, in general, possesses ; by virtue
of which it has the capacity, or aptitude, to be
acted upon by the agency of external means,
PROPERTIES OF MATTER. 147
we rather search for the properties which external
means have produced upon it; and,
instead of separating, confoundfigure and extension
together. It will, however, appear,
that if matter, whether solid or fluid, while it
subsists in a common state, possessed, originally
and essentially, any of those secondary
qualities that are ascribed to it of figure, or of
color; it would, in that case, be altogether unfit
to answer the ends for which it was especially
designed : it could no more subserve the pur-%
poses for which it is employed by animated
beings, (for whose use, it is reasonable to presume,
it was intended,) than matter convey
nourishment to the living system, whilst it resisted
the digestive power of the stomach.
This state of original deprivation of all secondary
quality in solid matter, is equally
referrible to liquid ; to that element \vhich may
be considered as constituting the principal source
and support of fluidity in general. If water
possessed flavor together with fluidity, it would,
in such a case, be the flavor of the water that
was tasted, and not the flavor of the substance
which the water was intended to dissolve, or to
support : if water were salt or sour bitter or
sweet sapid, instead of being insipid altogether,
those secondary qualities would constantly
manifest themselves, and the quality of
the receiver would always adulterate and obli-
L2
148 ‘ ELEMENTARY PROPERTIES
terate the quality of the thing received. If we
extend our views to air and light, we shall find
that, although each of these bodies possesses
properties of its own, which are Inseparable
from the extension which they contain, that
they are, nevertheless, originally destitute 6f a
variety of thos^ secondary qualities which are
‘often ascribed to them, but which they afterwards
factitiously obtain. With respect to
fcir, it bears the same relation to sound, that
water does to flavor ; or that the block does
to figure ; if air possessed any particular
^sound of its own, that sound, like the figure
upon the canvas, would constantly manifest
itself; either, when it was impelled by mechanical
means through musical instruments in
general, or, through the vocal organs in particular
; instead of harmony, discord must be
produced. Air possessing, however, the primary
and essential attributes of expansibility
Blone, it has the power to expand, and the
capacity to be compressed ; to be modulated
atid harmonised by the energy resident in the
Organs of speech ; and, by their instrumentality
language is produced. The satne observations
equally apply with respect to resistance. If the
medium of air, through which the rays cf light
are conveyed, instead of being diaphanous
and permeable, were turbid and colored ; the
rays of light, instead of being transmitted,
OP COMMON HATTER. 149
would be arrested by the air, as they are found
to be, by the opacity of a cloud, or of a fog;
and if the air were colored, the light in its
passage through it, would be constantly tinged
and dyed by the color of the medium. That
this would be the case, is clearjy demonstrated,
by the effect which is produced on the rays of
light when they pass through the medium of
glasses stained with different colors ; the color
of the glass is always found to stain the rays of
light, and convey to the eye its particular color
: through a green glass, a body looks
green ; through a red glass, it looks red ; and
the influence which a jaundiced eye possesses,
of rendering bodies seen by it to appear yellow,
has been often noticed.*
The different states of the medium which I
have described, may be considered as unnatural
and morbid ; arising from the union and
diffusion of different bodies, which have insinuated
themselves into it. If the colored state
of the medium through which objects are beheld,
produces these unnatural consequences,
*
Although I have known this sensation occasionally to
happen, it is not generally the case ; when it does happen, it
is only in those extreme cases ofjaundice, when a large quantity
of bile has been absorbed, and conveyed into the blood ;
and incorporated to a considerable degree, with the cornea
and the humors of the eye.
150 ELEMENTARY PROPERTIES
how much more must these unnatural consequences
be produced, if the rays of light are
themselves colored originally and essentially!
If, in fact, the light which proceeds from
the sun to the earth, consists, as Sin ISAAC
NEWTON has asserted, (and as it is, at this time,
generally believed,) of seven colors, which, possessing
different degrees of refrangibility, may,
in consequence, be separated from each other,
by means of a prism, and seen to display the
several colors of red orange yellowgreen
bfae! indigo and violet ; that these seven
different colors are original and simple ; and
that all the colors in the world, either consist
of these simple colors, or of compounds, formed
out of them, mixed together in different proportions.
If this hypothesis were true, that the rays of
the sun, the pure matter of light, were colored,
the inevitable consequence would be, that all
the bodies which were conveyed to our organs
of vision, would be constantly tinctured and
dyed by the particular colors of those rays.
It would not be the specific and identical color
of the object itself, that we should behold, but
the individual colors of the rays alone. Thai
this would be the fact, may be proved in a
manner the most satisfactory and decisive. If
a beam of light be separated by a prism, into
the seven prismatic colors, and any substance
OF COMMON MATTER. 151
placed in the image formed by each separate
ray, the color of the substance always participates
the color to which it may have been
exposed ; in the red ray, the substance appears
red ; in the orange ray, it assumes an orange
color ; in the green, a green color ; and, so on
of the rest; instead of the infinite variety of
colors, by which we behold every particle of
matter characterised, color would be entirely
limited and confined to the prismatic only ; to
seven, as SIR I. NEWTON supposed, or even
to three, as they are now reduced ; or, to the
modification which might be formed, in consequence
of their union in different proportions*
The result would be, the production of some
color, varying, it is true, in appearance, from the
separate color of each individual ray, but altogether
different from the specific tinge, or dye,
which I contend the ray of light has received, by
uniting with the body on which it falls, and from
which it was reflected ; conveying with it the
tinge, or dye, as it were, of the substance, to
the organs of vision. The state of deprivation
which the sun is in, respecting color, is equalJy
referrible to fire.
Although the sun has been generally considered
the original source whence fire was
derived ; every fact of which we are in possession,
when properly examined, will be found to
militate against this opinion. If the sun is a
globe of fire, it must, in every respect, be situ152
ELEMENTARY PROPERTIES
ated with relation to surrounding objects i*
general, and to this world in particular ; in a
manner similar and analogous to any collected
mass of sublunary fire : its power may differ in
intensity, but its influence must be the same ;
so far, however, from the effects which flow
from both, being one and the same, they are
found to be totally different from each other.
It may be considered as a general truth, that
these effects continue to increase in a progressive
degree, in proportion as the fire is approached,
and that its maximum of power is
more especially displayed, when foreign bodies
are in immediate contact with it With respect
to the sun, the effects are altogether different ;
if the sun is a globe of fire, it must, as a
consequence, follow, that the degree of heat
and of expansion which it excites, ought uniformly
and progressively to increase, not only
in proportion to its proximity to us, but more
especially, according to the purity and rarity of
the medium through which the rays of the sun
are transmitted. Although the temperature
varies, in an infinite degree, in different latitudes,
from the line of the equator to the poles, when
the temperature is measured on the plain surface:
at the highest point of elevation, on the
contrary, a generalauniformity is found to exist;
so far from the temperature increasing as we
ascend, the very reverse takes place; the tempeOF
COMMON MATTER. 153
rature perpetually decreases to such a degree,
that the climate is altogether unfit for animal or
vegetable life, and the intensity of it can only be
apprehended, by the vast coverings ofsnow and
of ice with which the summits of the most lofty
mountains, in all parts of the world, whether
situated at the polar or meridional regions, are
everlastingly coated. That this is the fact, will
appear, if the temperature of different latitudes,
at the same degree of altitude, be compared with
each other. Although the highest mountains of
this island may be considered as mere dwarfs,
when compared to those of the continent, in point
of density and elevation, the decrease oftemperature
is, nevertheless, very perceptible with the
increase of elevation ; while the thermometer
was at 63. last August, at the base of Skiddaw,
the mercury gradually fell, in ascending towards
the summit of that mountain, as low as 34*.
This great diminution of temperature from the
base to the summit, is more especially found to
subsist in Mount ^Etna Vesuvius and Olympus
the peak of Teneriffe the Alps and Appenines
the Andes and Cordilleras those
gigantic mountains that are surrounded by
burning sands, and situated at the equator ;
whose position, with respect to the incident solar
ray, is vertical ; whose elevation is so high, that
the rarity of the atmospheric medium, through
which the rays are transmitted, is, in a great
154 ELEMENTARY PROPERTIES
degree, free from atmospheric pollution ; and is
as incapable of opposing to them resistance, as
it is to bereave them of igneous power. If the
sun, therefore, were a globe of fire, instead of
the summit of these mountains being everlastingly
coated with ice and snow, neither the one
nor the other ought ever to be seen ; and, instead
of the temperature being higher at the bottom
of a mountain than at the top, it ought to be
higher at the top than at the bottom.
We are, therefore, driven to the necessity of
concluding, that, notwithstanding the mixture
and opacity of the medium, in which we exist,
is involved ; that there subsist in it, rays of light,
that are neither hot nor cold fire nor ice
black nor white yellow nor green orange
nor red purple nor violet but that are transparent
and colorless only ; that are as colorless
as air is speechless as much as water is tasteless,
or, as solid matter is self-motive ; but
that are destitute of every essential and original
quality, extension and motion alone excepted.
Consequently, it may be presumed, that the
sun itself as the parent whence the rays of pure
light proceed, is a globe of light only.
If the rays of the sun were, inherently, to
possess any other attributes than those of extension
and motion, the effect would be different
from its cause ; one of the fundamental laws of
nature would be subverted arid destroyed ; and,
OF COMMON MATTER. 155
a consequent inversion of principle would ensue;
instead of elementary and causal bodies
producing effects according to their own nature;
instead of the effects being secondarily, what
the cause is, primarily, no correspondence or dependence
would exist between the effect and
the cause. The eye, therefore, might as easily
become the organ of hearing, the ear the organ
of seeing, a* for light to possess any other attributes
than those I have already described.
It is far otherwise ; every effect that is produced,
is not only the result of a power resident in
a cause, but in every case, and under every
possible circumstance, the power of the cause
transcends the power of the effect that flows
from it. The element of light, therefore, subsisting
in the sun, is as superior, in brilliancy,
to its rays, as the purest light of the brighest
day, is superior, in brilliancy, to light obtained
from those bodies by which it is exhibited and
evolved; the rays of the sun, therefore, continually
lose part of their purity, as they descend
to the earth,
SECTION II.
Oti the Source and mechanical Power of Light.
THAT the sun is the principal source, the
fountain and the reservoir, whence the mat156
ELEMENTARY PROPERTIES
ter of light originates and proceeds ; appears,
I may be allowed to say, a self-evident truth.
It is proved, positively, by the illumination
which we enjoy, and by the facility which we, in
consequence, possess, of beholding surrounding
objects, when it is present to our view. It is
proved, negatively, by the total state of obscurity
and of darkness, in which we are involved,
when in the course of planetary revolution,
we are deprived of the benefit of the sun’s
rays ; with the exception, perhaps, of the light
which might flow from the planets, and from other
bodies, which have, either directly or indirectly,
received its influence, the world, at large,
would be involved in darkness the most impenetrable
and profound. It is an indelible truth,
that the region which we inhabit r-the world in
which we exist every particle of matter of
which it is composed with respect to light,
subsists in a state of total and absolute privation;
there is no light originating in it, or
belonging to it ; no light, but rather darkness
visible ; and the light, in short, which we enjoy,
is not native, but exotic ; not inherent in any
part of the system to which we belong, but
altogether derived from the planetary system
in general, and the sun in particular.
Splendid and brilliant as is this attribute, of
exciting the sensation of illumination on the
organs of vision, with which animated beings
OF COMMON MATTER. 157
are endowed, it must, nevertheless, be admitted,
that the velocity with which it moves, and
the extreme subtilty and exility of which its
particles are constituted, are equally deserving
our admiration and astonishment. Although
these attributes, from the very nature of them,
might be expected to evade the researches of the
most learned : the attentive observation of the
ingenious have, nevertheless, in some measure,
succeeded in ascertaining the degrees of the
one, as well as of the other. Among the most
illustrious of these, may be mentioned Dr.
BRADLEY, REAUMUR, and CASSINI ; the data
on which they proceeded, with respect to the
motion of light, were founded on the eclipses,
which the satellites or moons of the planet
Jupiter, undergo. By observation, they found
that the eclipses of these satellites appeared, in
fact, sooner than they ought, by hypothesis, to do,
when Jupiter was nearer to the earth ; and later,
When that planet was on the farthest side of her
orbit; or, in other words, that the time when
these eclipses appeared, was always influenced
by the degree of distance. By observations, such
as these, they were enabled to show, that
although the motion of the solar rays, is not
instantaneous, but progressive it, nevertheless,
flows with the astonishing velocity of 200,000
miles in every second of time; so that, admitting
the sun to be 95,513,794 English miles
158 ELEMENTARY PROPERTIES
distant from this earth, the rays which issue
from the sun reach the surface here below, in
the short space of 8 minutes, llg seconds of
time ; a distance which could not be traversed
by the swiftest ball that was ever fired out of
the largest cannon, in less time than thirty-two
years ; admitting, what is impossible, that it
continues to preserve its initial velocity of one
mile per second of time.
If the solar rays possessed a correspondent
degree of density or of motive power, the combined
effect the momentum, (i.
- the quantity
and velocity compounded together,) would produce
an impulse which would be capable of
overcoming the resistance which could be opposed
to them by the densest and hardest
matter, existing in the system of nature. The
eyes of animated beings, in particular, to whose
use the solar rays are more especially designed
to subserve, would be torn asunder, and totally
disorganised; for, as Mr. NICHOLSON very
justly observes, that the momentum of a body
is, as its mass multiplied by its velocity, and
as the solar rays were in the excess of 200,000
to 1 to a cannon ball, it must follow, that, if the
particles of light were equal, in mass, to the
two-millionth part of the smallest grain of sand,
we should be no more able to endure their
impulse, than of the sand when shot pointblank
from a cannon. In illustration of the
OF COMMON MATTER. 159
above opinion, I shall merely quote a passage
from Dr. THOMSON’S valuable System of
Chemistry.
” A 29lb. ball, if thrown from the
hand, makes no impression upon a common
wall, but when discharged from a cannon with
the velocity of 1300 feet in a second of time, it
will then be found to shatter the wall to pieces:
the greater velocity, therefore, with which a
body moves, the greater the effect which it is
capable of producing; consequently, to produce
any effect whatever, by a body however
small, we have only to increase its velocity
sufficiently; and, in order to prevent a body
from producing a given effect, its quantity must
be diminished, in proportion as its velocity is
decreased : now the velocity of light is so great,
that if each of its particles weighed the 1000
part of a grain of sand, its force would be
greater than that of a bullet, discharged from a
musket; were it even the millionth part of a
grain in weight, it would destroy every thing
against which it struck : if it even weighed the
millionth part of that, it would still have a very
sensible force; but how much less must be
the weight of a particle of light, which makes
no sensible impression upon so delicate an organ
as the eye? We are certain then, that no
particle of light, is 1,000,000,000,000th of a
grain ; but were we even to suppose it of that
size, the addition of 900 millions of particles
ELEMENTARY PROPERTIES
to anybody, or their abstraction, would make
no difference of weight capable of being detected
by the most sensible balance ; eery attempt
then to ascertain the accumulation of light in
todies, by changes in their weight, must be hope-
It is owing to this extreme state of exility,
connected with the inherent power of moving,
which the solar rays possess, that they are
enabled to penetrate the internal fabric of
bodies in general, whether diaphonous or opake.
This penetrating power is proved to be possessed
by them, from the impressions which they
excite on our organs of vision ; such is the compact
nature of the comm, or external coat of
the eye, that without this subtilty, the solar
ray, instead of penetrating it, would be arrested
by it, as well as by the other parts of which the
internal fabric of the eye is composed, and
never arrive at the membrane on which the
retina is spread, in which the impression is
deposited, and illumination produced. This
penetrating power is equally proved, by the
illumination which we, in consequence, enjoy
from it, through the medium of different bodies,
and more especially of our windows, insomuch
that glass (which is supposed from its inelasticity
to have its particles most intimately combined
-and compacted) of the most solid quality,
to its passage, neither impediment nor
OF COMMON MATTER. 161
Obstruction. It is further proved by the utter
impossibility which exists, of exhausting- the
solar rays out of a glass receiver, after the other
parts of the atmospheric materials have been
pumped out of it.
Such, indeed, is the extreme subtilty of the
solar rays, that their materiality has been questioned.
I do not mean to range myself under
the banners ofthose who entertain these doubts :
to me it appears, that the materiality of light is
as decisively proved, as the materiality of any
species of matter whatever. The impressions
excited upon the different organs of sense by
external objects, of ice, or of fire, in producing
the sensation of cold or of heat of air upon
the auditory nerves, in exciting the sensation of
sound of volatile bodies upon the olfactory
nerves, in exciting the sensation of odor, &c. &c.
are not more evident and characterised, than
the power which the solar rays possess, of penetrating
the cornea, or external coat of the eye ;
and, after undergoing different modifications,
from the different media through which they
pass, of arriving at the bottom of the eye, on
which the retina is spread, sensation excited,
and illumination produced. The materiality
of the solar rays is proved, by the space which
they fill, and by the illumination which they
excite. It is proved by the facility with whick
M
162 ELEMENTARY PROPERTIES
a beam of solar matter may be reflected and
refracted, and either condensed to a focal
point, or segregated into parts, and each part
produce upon the eye a diversity of impressions.
The materiality of the solar rays is further
proved, by the chemical effects produced
on different bodies which are exposed
to their influence. By their influence, vegetables,
which, in the dark, were pallid and
white, are found to recover their natural verdure
and bloom; by their power, water becomes
gassified ; metals calcified ; and other bodies
modified and changed to such a degree, that
they acquire properties altogether different
from those which they before possessed.
Although the materiality of the solar rays
appears to me an incontrovertible truth, the
mode by which its effects are produced, has
been a source of difference among natural
philosophers. HUYGENS, DES CARTES, and
EULER, considered light to be a subtile fluid,
filling space, and thrown into undulations by the
sun ; which undulations extending themselves
to the eye, render bodies visible. Sir ISAAC
NEWTON, on the contrary, considered light to
be a real substance, consisting of small particles,
which perpetually emanating, in straight
lines, from luminous bodies, and entering the
eye, excite the sensation of vision, or the perOF
COMMON MATTER. 163
ception of those objects whence the light
arose.
It is not surprising that matter .of this subtile
description should have evaded the inquiries
of the most enlightened and attentive ; and,
that they were reduced to the necessity of proceeding
from assumptions, instead of axioms ;
and, of concluding from hypothesis, instead of
demonstration.
The separation of a beam of atmospheric
color, through the medium of the prism, into
seven distinct parts, although not so antient
as the variegated colors, manifested by what is
called the rain-bow, is nevertheless, no modern
discovery. Sir Isaac Newton, in particular, may
be said to have nearly exhausted the subject.
It is, however, to Dr. HERSCHEL, to whom the
merit, unquestionably, belongs, of having separated
the element from the accident, the pure,
colorless light, from the compound and visible
color. As these experiments are detailed, at
large, in the Philosophical Transactions for
the year 1800, have been copied into different
periodical publications, and are well
known ; I shall merely state the general result
of them in this place, and refer the reader
to the original communication. When a prism
is properly adjusted, at a suitable distance from
a sheet of white paper, on which the spectrum,
M 2
ELEMENTARY PROPERTIES
is received, it becomes, as usual, subdivided
into seven different parts ; each of which, possessing
different degrees of refrangibility, becomes,
consequently, separated from each other ;
and the several colors, which are known by the
appellation of prismatic colors, are made visible.
Dr. Herschel found, that by placing a
very sensible thermometer beyond the colored
spectrum, external to the boundary of the red
ray, but still in the line of the spectrum, the
mercury rose much higher, than when it was
exposed to the immediate action of the red ray;
and, on shifting the thermometer still further
from the colored image, the mercury continued
to rise, and did not reach its maximum, until
it was placed half an inch beyond the utmost
extent of the red-colored ray.
By the power of this invisible ray, as it has
been called, but which I shall denominate
colorless, the metallic oxydes were reduced ; and
Dr. WOLLASTON, w7ho has since made a number
of experiments on the same subject, found,
that the muriate of silver was blackened more
rapidly, when exposed to its influence alone,
entirely beyond the reach of the prismatic
spectrum ; and, finally, that this change was
accomplished without the production of any
sensible increase of heat. Had it not been,
indeed, for the sensible phenomena produced
on the thermometer and other bodies, exposed
OF COMMON MATTER. 165
to its power, it would have remained as unknown
to us, at this time, as it vyas to Sir Isaac
Newton, a century ago.
Is it not reasonable to suppose, that it is this
actual and individual ray, which penetrating
bodies the most diaphonous and solid, remains
in them in a latent^ invisible, insensible, and
uncombined state; and afterwards radiates
and issues out of them in a state of combination,
manifesting* the phenomena of color and
of temperature; and, that it is this ray, which
has been so long known under the appellation
of latent heat ?
On an attentive review of the attributes
which seem essentially to belong to light,
I am led to conclude, that in its nature, it is totally
and absolutely different from every other
species of matter, of which we have any knowledge.
The phenomena which it describes decidedly
prove, that it is of a quality sui generis.
Instead of supposing light to be solid, massy,
and impenetrable, I contend, on the contrary,
that every phenomenon which it describes,
shows that it. is the most fluid, the most subtile,
and the most penetrable that can be conceived ;
that, instead of being inert and heavy, it is
essentially active and imponderable. Instead of
moving like the matter belonging to our world,
by a power from without, the solar rays traverse,
with the most incredible velocity, the
166 ELEMENTARY PROPERTIES
wide expanse of the planetary spheres, excit,
ing the sensation of illumination on the optic
organs of animated beings, by a power from
within, inherent and essential ; participating,
in a most eminent degree, the quality of
the cause of which it is the immediate
effect. Instead of supposing that the sun,
as the source of light, actually possesses an
attracting power, the motion of the matter of
light, from the surface of the sun, shows that it
is repulsive, in the greatest degree that the imagination
can conceive. Must it not, indeed, be
obvious to the most common capacity, that if
the sun were an attracting body if a power,
such as this, existed in the sun, as the source
whence the rays proceed, the rays instead
of corning out of it, &ould be attracted by
it, and retained in it ; the solar rays would
be as fixed, arid as immoveable in the body
of the sun, as the solid nucleus of the earth
itself; insomuch, that the universe at large,
would be involved in absolute and utter darkness.
Instead, therefore, of subscribing to the
opinions which have been long entertained,
that all the matter of the universe, is the
same in nature, and in kind ; and that the
diversity of the phenomena, which particular
portions of matter display, proceeds from
the various modifications, and commutatiOF
COMMON MATTER. 107
ons, which the same original particles are
made to undergo I contend, on the contrary,
that the original particles of which
the different elements are constituted, are
originally and essentially different. I contend,
that the solid matter is not only essentially
different from the liquid the earth
from the water both different from air and
fire ; and all of them different from the solar
rays ; and as a consequence of the diversity
in the attributes of each, that it is most
unphilosophical, and unscientific, to ascribe
the phenomena, or effects, which each of them
severally displays, to the operation of one
and the same law. Finally, it may be presumed,
that the various observations which
have been made, by Dr. HERSCHEL, and other
celebrated astronomers, on the nature of the
dark and opake matter, of which the body of
the sun is supposed to be composed, are optical
errors, from the imperfection, and insufficiency,
of the instruments employed ; that these
spots, instead of constituting different integrant
portions of the sun itself, are rather to be considered
as collected masses of opake matter,
interposed in the medium alone ; that from the
fugitive and evanescent nature of these spots,
it is reasonable to suppose, that they exist
below the disc of the sun, and are out of it
;
ELEMENTARY PROPERTIES
that they are totally unconnected with it, and
form no part of its body.
In venturing to draw such a conclusion,
I shall not, I trust, be accused of greater
presumption than is ascribable to those distinguished
characters, who attempt to explore,
and to ascertain, by means of telescopes,
the absolute nature of the matter of
which the sun is composed ; more especially,
when we reflect on the immense distance which
it is known to be situated from the surface
of the earth, and on the absolute necessity
which exists, of blackening the lens, through
which the rays pass, in order that the orbit of
the eye may be protected from the ardor of their
lustre.
The insufficiency in the means, has been particularly
acknowledged by Dr. Herschel himself.
The last number of the Philosophical
Transactions, contains a very interesting paper
from him, entitled,
” Astronomical Observations,
relating to the Construction of the heavenly
Bodies ;” in which he makes a marked
distinction between matter of light, or what
he denominates nebulous matter, and other
kinds of matter; and that from the nature
of its quality, and the variety of appearances,
which under different circumstances,
it assumes, it is probable, that our best inf)
F COMMON MATTER. 169
struments, will not reach so far into the profundity
of space, as to see more distant diffusions
of it ; and from the variety in the dimness,
faintness, and brilliancy of different bodies,
we may already surmise that the range of
the visibility of the nebulous matter, is confined to
very moderate limits ;” and, in order to enforce
this opinion, he repeats, at page 279,
” that
the range of the visibility of nebulous matter,
is what may be called very limited ; and
further observes, that it cannot be expected,
that such nebulosities will remain visible,
when exceedingly farther from us than the
precise nebula ; the ratio of the known decrease
of the light, will not admit of a great
range of visibility, within the narrow limits,
whereby this shining substance can affect th
eye ; and if our telescopes cannot be expected
to reach the nebulous matter, the actual quantity
of its diffusion may still farther exceed,
even the vast abundance of it already proved to
exist.”
It is impossible for me to mention the name
of HERSCHEL, without feelings of the greatest
respect. The Philosophical Transactions contain
a variety of papers from him, which
abound with a multitude of observations on
the construction of the heavenly bodies, and
of the quality of the matter of which they
are composed. In some of these papers, lie
170 ELEMENTARY PROPERTIES
seems to think that the body of the sun
is solid and massy, like any other species
of matter; but that the light, with which
the planetary spheres are illuminated, proceeds
from a luminous atmosphere, by which
the sun is surrounded ; and, that it is through
the crevices, or breaks, which sometimes take
place in the luminous matter, that the body
of the sun itself, is occasionally to be seen.
In the present essay, with a degree of candor
which does him honor, he frankly confesses,
that from greater, and more repeated, observations,
on the arrangement and magnitude of the
stars, and some other particulars, his opinions
have undergone a gradual change; and, that it is
not surprising, that many things formerly taken
for granted, should, on examination, prove to
be different, from what they were generally,
but incautiously, supposed to be. He considers,
or rather defines, nebulous matter to denote
that substance, or rather those substances,
which give light, whatsoever may be their nature,
or of whatever different powers, .they may
be possessed ; and that this nebulous matter is
not equally bright in all its parts, but that its
light is more condensed, in some places, than in
others. He uses the word condensation as the
most intelligible that he can employ. He conceives
that we can only account for the greater
brightness towards the middle of the nebula,
OF COMMON MATTER. 171
by supposing, that the nebulous matter of
which it is composed, fills an irregular kind
of solid space ; and that it is either a little
deeper in the brightest place ; or, that the nebulosity
is, perhaps, a little more compressed.
A moderate condensation, accompanied with
some little general swelling of the nebulous
matter, about the places which appear like
nuclei, will account, he supposes, for their
superior brightness ; and that several bright
nuclei, are rendered visible thereby.
The difficulty, however, of ascertaining the
probable cause of this condensation, in matter
so extremely repellent as this luminous
matter appears to be, naturally presents itself;
the subject is soon settled: instead,
says the doctor, of inquiring after the nature
of the cause of the condensation of nebulous
matter, it is sufficient for the present
purpose, to call it merely a condensing principle
; but since we are already acquainted
with the centripetal force of attraction, which
gives a globular figure to planets, keeps them
from flying out of their orbits in tangents,
and makes them revolve round one another,why
should we not look up to the universal
gravitation of matter, as the cause of every
condensation, accumulation, compression, and
concentration ofnebulous matter ? Facts are not
172 ELEMENTARY PROPERTIES
wanting, he says, to prove, that such 3,
power has been exerted, and that the globular
form of the nebulous matter, deduce4
from the round appearance of the nebulas,
may be ascribed to the action of the gavitating
principle; and, from the united testimony
of so many objects, no doubt is left about
the central seat of attraction, which in every
instance of figure is pointed out to be in the
middle ; the exertion of this supposed condensing
principle in some nebulae, it is inferred,
has been the means of producing in some of
them, a very moderate effect ; which may, perhaps,
be ascribed to the small quantity of the
preponderating, central, attractive matter ; or,
even to the shortness of its time of acting, for
in this case, millions of years are, perhaps, but
moments. In the case, however, of very narrow,
long nebulae, we may investigate the form
of the expansion of nebulous matter, by the
figure of the nebulae that have been observed,
and may be considered as consisting of their
disunion ; the most plausible way of accounting
for the apparent figure of these nebula, is
to admit that the expansion of the nebulosity
consists, indeed, of a very narrow light, and
not much depth. Granting it to be highly probable,
that the appearance of irregular round
nebulae, is owing to so many irregular gloOF
COMMON MATTER. 173
bular expansions of nebulous matter ;
it is necessary
to inquire into the cause that has
formed this matter into such masses. To ascribe
it to chance is unphilosophical ; especially as
a forming cause offers itself to our view, when
we direct our eye to the globular figure of the
planets, and satellites, of the solar system!!!
and we may confidently assign the attraction of
gravitation, as the principle which has drawn
the nebulous matter towards a centre, and collected
it in a spirical ctimpass. In the course of
the gradual condensation of the nebulous matter,
it may be expected, that a time must come,
when it cati ho longer be compressed, and the
only cause which we may suppose to put
an end to the compression, is when the
consolidated matter assumes hardness. When
we reflect on these circumstances, we may
conceive, that, perhaps, in progress of time,
these nebulae, which are already in such
a state of compression, may be still farther
condensed, so as actually to become
solid.
I have deemed it proper to give this short
abstract from Doctor Herschel’s paper, on
this interesting subject; but it must, however,
be observed, that we ought carefully
to separate the matter of fact, and of observation,
from the matter of opinion, as to the
174 ELEMENTARY PROPERTIES
causes by which the effects are produced,
which he has described.
SIR ISAAC NEWTON supposed,
” that the original
construction of matter was solid, massy,
impenetrable ; that these solid primitive particles
are incomparably harder than any porous
bodies composed of them, and that they were
so hard, as never to break in pieces. While
the particles continue entire, they may compose
bodies of one and the same nature and
texture, in all ages ; but should they wear
away, or break in pieces, the nature of all
things, depending on them, would be changed.
Water and earth composed of old worn-out
particles, and fragments of particles, would
not now be of the same texture with water and
earth composed of. entire particles in the beginning;
and, therefore, in order that nature
may be lasting, the change of corporeal things
is to be placed in the various separations, and
new associations and motions of these permanent
particles ; compound bodies being apt to
break, not in the midst of solid particles, but
when these particles are laid together, and
touch in a few parts. These particles have not
only a vis inertia accompanied with such laws
of motion as naturally result from that force,
but also are moved by certain active principles ;
a.s gravity, and that which causes the fermentaOF
COMMON MATTER. 175
tion, and the cohesion of bodies. The principles
are not to be considered as occult qualities,
supposed the result from the specific form of
things, but as grand laws of nature, by which
the things themselves are formed ; the truth appearing
to us by phenomena, though the cause
is not yet discovered.”
CHAFfER VIII.
ON THE MEANS BY WHICH COMPOUND BOWES
ARE FORMED.
IT has been my especial object, so far as I have
gone, to prove, that all the phenomena which take
place in the universe, are effects only of producing
causes ; that these effects are ends, ofwhich
there, of necessity, must have been a beginning;
that the power which was from the beginning,
is the cause to which the ultimate effect is to
be referred; (e. g.) action is the effect, of which
organisation is the cause ; organisation is the
effect of which the principle of life is the cause ;
thinking is an effect ofwhich the thinking principle
is the cause. All the children of any one
family are ends of which their parents are the
beginning; these parents are the offspring of
former parents ; the succession, therefore, may
be traced, of animals and of vegetables, to first
parents ; to first parents which did not produce
FORMATION OF COMPOUND BODIES. 177
themselves, but which were produced by some
other being : and, as every thing which is
created, must, of necessity, have had a Creator;
(because nothing which is created can be the
cause of its own creation) a time must have
been when the first vegetables were created
without seed, the first animals without intercourse.
The same observations equally apply
with respect to the existence of compound bodies,
formed from those that are simple. It
might as well be supposed, that the different
organs, of which living beings are composed,
were formed before the power which formed
them had any actual existence, as to affirm that
compound bodies existed before their elemen^
tary parts.* The qualities of those ingredients
* The nature of the power subsisting as a cause, by whose
energy various effects are produced, would, in this place,
be a proper object of inquiry ; but persuaded as I am, that
such an inquiry would not only, perhaps, be fruitless, but to
a certainty, ill received, I shall, for these reasons, avoid it.
It is, nevertheless, important to observe, that the learned
author of antient metaphysics, observes, that both nature
and artt have the same end in their operations ; and that
when the end is obtained, the thing operated upon, is in a
state of perfection, or completion ; that in the operation of both
nature and art, there is a progress, and, by consequence, a
change from one thing to another; and that this change is
motion. It is, however, very evident, that as every thing
which exists, whether by nature or art, was before it existed
possible to exist; it must, therefore, have existed
N
178 FORMATION OF COMPOUND BODIES.
(which may very properly be called elements.*
with relation to the ultimate effect) are altogether
different in their simple, from what they
are found to be in their combined, state ; insomuch,
that the definition that would point out
the nature of the one, would, in no way, apply
to the other. It is, therefore, of importance,
that we should endeavour to trace the means by
which such an infinite multitude of bodies exist,
out of elements which are, apparently, few in
number, and whose properties are certainly
different from what they were before.*
If all the matter of which the universe
is composed, had been of one simple elementary
kind ; or if that element, like the solid
in capacity, before it actually existed in energy^-In this
way he conceived that plants exist in the seed animals in the
embryo-works of art, in the idea of the artist ; and, in
short, that every thing which is made, existed in the cause by
which it was produced ; the thing, therefore, which was produced
by capacity towards energy, from what to what, is
the state between both, having a connexion between each of
them.
* If the principle of vitality had been the same throughout
the wide range of animated existence, all animals and vegetables,
instead of being different in nature, and in kind, would
have been alike in figure, and in form ; and, if attraction, and
the principle of attraction, exerted its energy on matter of the
same kind, it is probable that all the matter of the universe,
would either be all pasivity, or all power; all inertness, or all
activity.
FORMATION OF COMPOUND BODIES.
matter of earth, had been doomed to be passive
and inert, no change in nature could have
taken place ; it might have undergone different
changes, by the agency of external means but
destitute, as it naturally ‘is, of any inherent
power, of action, or of motion, it would have
continued, uniformly and invariably, the same,
during the long course of revolving ages.
The same consequences would have ensued,
if the matter of the universe had been either
fluid or gaseous only ; and more especially,
if it had been evssentially, and inherently,
solid and impenetrable.
It is far otherwise. In the system of nature,
webehold matter which possesses different powers,
and different capacities, oraptitudes, some
species that are totally active, others that are
totally passive ; some that move, others that
are moved ; some that combine, and others
that caneot resist combination. It is by virtue
of this difference which exists in the quality of
matter of different species, between the power
of some, and the weakness of others, that the
jrario’us combinations which take place throughout
the system of nature, are principally to be
referred.
When two volumes of air of the same
kindor two quantities of water, are added
together, an increase of bulk takes place in
them, in proportion to the quantity of matter
N2
180 FORMATION OF COMPOUND BODIES.
which is applied, but no other change of property
ensues. Although this accumulation has
been accomplished, by external means independently
of any internal, or inherent influence ;
it is often called by the title of the attraction of
aggregation : very different, however, it must
be confessed, are those accumulations of parts,
heaped up together by external influence, from
that bond of union by which we behold the
most minute particles of matter spontaneously,
as it were, held together. This union
is called adhesion; and the power which it
is supposed holds and binds them together,
is called attraction; adhesive attraction, or
the attraction of adhesion, is the phrase usually
employed to designate the connexion which
exists between them.
When different species of matter are brought
in contact together, and a union between
them takes place, instead of aggregation
simply, each of the bodies loses some of the
properties which it originally possessed, and
the compound which is formed, is altogether
different from the quality of the elements, or
ingredients, of which it is constituted ; arid as
some bodies are found to have a stronger tendency
to unite together, to the exclusion of
others, this preference is called affinity, or
election; and the power by which the union is
accomplished, like the bond by which the
FORMATION OP COMPOUND BODIES. 181
particles are held together, is called attraction.
The whole together is known by the name
of chemical affinity, or elective attraction.
Attraction, therefore, properly considered, may
be supposed to bear the same relation to the
union of the particles of common matter together,
that I have endeavoured to show, vitality
(or the principle of life) bears to that which is
living. While vitality is the bond, and the
power, by which the particles of organised
matter are united, and the various phenomena
of organisation produced ; attraction, on
the contrary, may be considered as the bond,
and the power, by which the individual particles
of common matter are connected; not
only in parts, but in whole it forms the source
from which the various phenomena which different
species describe, are made to flow ; and
from whence secondary or accidental qualities
arise.
The meaning which I have attached to the
term, attraction, is conformable to what is generally
understood at this time. By some it is
called,
” the power of drawing any thing ;”
” the cause by which bodies tend towards each
other, and cohere, till separated by some external
force,”
” the power, or principle, by which
all bodies mutually tend towards each other,
without regarding the cause, or kind of acti -n,
that may be the means of producing the effect.”
182 FORMATION OF COMPOUND BODIES.
SIR ISAAC NEWTON, in particular, employs the
term, attraction, in a manner the most indefinite
that can possibly be conceived ; it neither
denotes aiiy particular kind, or manner, of
action^ nor the principal cause of such action ;
but the tendency only in general, a conatus
accidendi, to whatever cause such effect may be
owing ; whether to a power inherent in the bodies
themselves ; or to the impulse ofan external
agent. In his optics, he says, Attraction may
be performed by impulse, or some other means ;
and he uses the word to signify any force, by
which bodies tend towards one another; and
again, in his first Principles, he notes,
” that
he uses the words, Attraction, Impulsion, and
Propension, to the centre, indefinitely ; and
cautions the reader not to imagine, that by
attraction, he expresses the modes of the action
in the different cases thereof, as if there were
any proper powers in the centres, which, in
reality, are only mathematical points, or as if
the centres, could attract : he considers centripetal
powers as attractions ; though, physically
speaking, it were more just to call them Impulses
; and adds, that what he calls attraction,
may possibly be effected by impulse, though
not a common, or corporeal, impulse ; or after
some manner unknown to us.”
Vague and indefinite, in its application, as
the term attraction actually is, when thus emFORMATION
OF COMPOUND BODIES. 185
ployed, it will answer every purpose, and reconcile
all contradictions; it will reconcile the
opposite, and contrary phenomena, of attraction
and repulsion the centripetal, and centrifugal
forces the motion of bodies downwards,
as well as the elevation ofthem upwards ; the
agg egation of a mass of mud, by the manual
labor of a gang of scavengers ; and the junction
of different bodies together, from chemical affinity
; and we shall be called upon, to admit
as true, the absolute solidity and impenetrability
of matter. So far, however, from solidity,
or impenetrability, being essential properties
of matter, we possess facts abundant, and
universal, to show that the primary particles of
matter, are both permeable and penetrable.
When we see water and air, and the different articles
of food which animated beings receive for
their nourishment and support, converted by
the process of assimilation, or of animation,
from a common to a living state, from insensibility
to sensibility,—from non-sense to sense,
from passivity to power, from immobility to
motion, without the penetrability of matter, no
such change could be accomplished ; if the
particles of matter were penetrable in part, and
not altogether, animated beings would form a
^ compound of life and of death,- of penetrable
matter, which had received the participation of
life ; and of matter impenetrable, which had
the power of resisting its influence.
184 FORMATION OF COMPOUND BODIES.
When we reflect on the penetrating powerof
the solar rays, and that the most solid and
compact bodies are melted and dissipated by
them* when they are concentrated, and brought
to a focus ; when we see the change total, and
complete, which takes place between different
portions of matter, by chemical combination ;
we shall be led to conclude that these effects,
can only have been accomplished, by the primary
particles of those bodies having been penetrated
; and that the new arrangements which
have taken place, altogether proceed from the
penetrability which the most minute particles of
matter have the capacity to undergo. The penetrability
of matter, may be considered as a fact,
which rests upon evidence the most notorious
and self-evident, and appears to be as demonstrable
as the attribute of extension itself. We
may be permitted to predicate the penetrability
of matter, without incurring the absurdity
which has been so much dreaded ; that in that
case, two bodies would necessarily exist in the
same place, at one and the same time.
An inquiry, therefore, into the source
whence compound bodies are formed, the nature
of the materials of which they are composed,
and in which their secondary qualities
reside, becomes absolutely necessary. I shall,
therefore, proceed to detail the various processes
classification and calorification, of refrigeration
FORMATION OF COMPOUND BODIES. 185
rand colorification. I am well aware, that in
endeavouring to connect the great chain of
effects, which are constantly passing before
our eyes with their producing causes, many
links are yet wanting ; I, nevertheless, am
of opinion, that we possess data sufficient, on
which a legitimate and natural system may be
established. If I fail in the attempt, I shall
only share the fate which my predecessors have
experienced ; and, therefore, claim for myself,
the same candor and indulgence which have
been shown to them.
CHAPTER IX.
ON THE PROCESS OF GASSIFICATION.
NATURAL philosophers have, at different times,
directed their attention to determine the agency
of that power, by which the conversion and preservation
of water into a gaseous, or aeri-form,
state, has taken place ; and its elevation upon
the surface of the earth, to high points in the firmament;
from the time that the earth was
without form and void, and darkness was
on the face of the deep, and the Spirit of
God moved on the face of the waters. DR.
HALLEY, MUSCHENBROECK, and others, supposed
that this effect was accomplished,
”
by a
chemical affinity, which existed between air
and water, so that the evaporation of water, at
a low temperature, depended on the mutual attraction
which existed between both ; they considered
it to be similar to the solution which
takes place of salt in water, the air dissolving
the water, as the water does the salt.”
PROCESS OF GASSIFICATION. 187
- HAMILTON, of Dublin, concluded, “that
evaporation is nothing else than the gradual
solution of water in air, produced and promoted
by (what he calls) attraction, assisted by heat
and motion, in the same manner as other substances
are affected.” Dr. Halley supposed
small hollow spheres of water, to be filled with a
subtile elastic fluid, which made them naturally
lighter than air ; and that a chemical union took
place between both ; air dissolving water, as
water does salt. DESAGULIERS argues, that
water is capable of being converted, by heat,
into an elastic fluid, much lighter than air ; and
ARISTOTLE ascribes exhalation to the action of
fire. LE ROY, of Montpellier, also supposed
that,
” air dissolved water, in the same manner
that water dissolved sugar ; as water, by being
heated, becomes able to dissolve a large quantity
of sugar, and of salt, and, by cooling, abandons
a part of what it had dissolved ; in like manner,
the air, as it became heated, or cooled, takes up
more or less water.” In order to ascertain the
fact, he exposed, athis window, during the night,
a white glass phial, full of air, closely tied up,
at the temperature of 79. Fahr: the mercury
fell to 68. during the night, and, on examining
the contents of the bottle, in the morning, he
found that a part of the water contained in the
air had separated, and had been deposited in
the form of little drops, which adhered to the
188 PROCESS OF GASSIFICATION.
interior sides of the vessel, which, being most
exposed, cooled the first; this accumulation
of dew became more abundant, as the thermometer
descended to 45. On exposing the bottle,
during the day, to the solar rays, the water
which had been separated during the night
from the air, became again converted into a
gaseous and vaporific form. These processes
of gassification of water, and liquefaction of
air, are always found to vary in a considerable
degree, by the influence of climates, of seasons,
of winds, and of weather, of days, and of
nights. It, nevertheless, appears that the evaporation
from ice, by the agency of the solar
rays, at a temperature considerably below 32*.
does not differ materially from that of water, at
the same temperature.
However various the means may be, by
which the process of gassification is effected,
we have evidence of the most decisive
kind, that in open space, it is greatly assisted,
if not altogether accomplished, by the
agency of the solar rays ; not only when they
issue from different bodies, into which they had
entered ; or, as they impinge on bodies whence
they are reflected ; and that it is to their power,
in particular, that the process of evaporation,
and of gassification, which is so extensively
carried from the surface of the globe, is principally
to be referred; by which, water, and
PROCESS OF GASSIFICATION. 189
other liquids, owing to the mkmte division to
which the particles, of which they are composed,
are susceptible, become acted upon, and
changed from a liquid, to a gaseous ; from an
inelastic, to an expansible, state ; leaving wet
places dry and dry places fissured and cracked;
making fogs and clouds undergo a transmutation,
from moisture to dryness, from opacity to
transparency, from inertness to motion, from
precipitation and fall, to suspension and dissipation,—
from capacity to power. It is during
this gaseous and gassified state ofthe atmosphere,
in which itmay be said to exist, in its most perfect
state of purity, and of perfection. Although it
virtually upholds, and contains, at that time, a
larger quantity of evaporated matter, which
before was opake and dense; that it is actually
most rare and transparent and with a larger
quantity of matter, which was incompressible,
inelastic, and moist; that it is most elastic,
compressible, and dry ; and most congenial to
the nourishment and support of animated beings
in general ; and to answer the other various
purposes for which it is designed, by the will of
the Almighty.
Various attempts have been made to ascertain
the quantity of water which has been evaporated,
and gassified, from a given surface.
Dr. HALLEY calculated, that the evaporation
which took place from the surface of the Me190
PROCESS OF GASSIPICATION.
diterranean Sea alone, was sufficient to yield
back all the water contained in the many
immense rivers which flow into it; and,
from the observations which were made by
Dr. WATSON, the present Bishop of Llandaff,
and which are detailed in his Chemical
Essays, for the purpose of ascertaining this
point, it appears that the quantity evaporated,
and raised from the surface of the earth,
exceeds what is generally believed : he says,
that at a time when there had been no rain
for above a month, when the grass was quite
brown and parched, the evaporation from
an acre of land, was not less than 1600 gallons,
in 24 hours ; and, in two experiments
made afterwards, when the ground had been
wetted by a thunder shower the day before, he
found, in the first experiment, the quantity of
water evaporated, was at the rate of 1973 gallons
per acre ; in the other 1905, within the
short space of 12 hours. From Mr. DALTON’S
tables it appears, that the evaporation
from a surface of water, is nearly twice as
much as from green ground ; that about eight
or nine inches of rain, are left for the supply of
springs and rivers, that this surplus of water
must be evaporated from the sea, and return to
it again by the rivers. We are likewise indebted
to COUNT RUMFORD, as well as to
MONS. SAUSSITRE, for various experiments and
PROCESS OF GASSIFICATION. 191
observations on this subject. While the experiments
of the former go to prove, that the
generation of pure air, takes place by the solar
rays acting upon water, but that it does not
take place in the dark : the observations
of the latter, in his laborious journey to the
summit of the Alps, shows the influence of
the solar rays in the process of gassification.
He observes, that in the most elevated regions,
the air is much drier than it is near the plain
surface; inasmuch, that in ascending to the
summit, his body was parched up, and the
ferrule of his carte actually dropped off. So
dry, indeed, is the air found to be at high points
of elevation, that it has been observed, that alkaline
salts, which at the bottom of amountain, will
very soon deliquesce, and run into a liquid state,
will, at the summit, remain exposed to the air
without showing the least sign of humidity.
Independently of these grand sources from
whence air and vapor are derived, there subsists
a variety of means by which they may be fictitiously
obtained ; an account of which, it is
unnecessary for me to give, as they are amply
detailed in the different works published at
different times, by eminent chemists, and are
constantly exhibited by the teachers of chemical
schools. It may, however, be stated, that
there is, perhaps, no species ofmatter whatever,
whether common, living, or dead, which does
192 PROCESS OF GASSIFICATION.
not, under certain circumstances, constitute the
agent, or the patient in the production of gassification.
We have direct evidence that every organised
system whatever, whether simple or complicated
whether vegetable or animal is in a
constant state of mutation, and decay; that all
are supplied with particular organs, by the
energy of which, the decayed particles are absorbed
and removed from the organs to which
they belonged ; and that they are excreted out
of the system, as matter dead and foreign.
Independently of the solid and liquid matter
which is thus expelled, there is also an abundant
quantity of gaseous matter, which, in animals,
is more especially expired from the
lungs and excreted from the surface ofthe skin.
The late Mr. CRUICKSHANK, and Mr. ARERNETHY,
with the utmost labor and pains, have
made a variety of experiments, for the purpose
of ascertaining the quantity of gaseous matter,
which is excreted from the skin only. Mr.
Cruickshank supposes that the cutaneous exhalation
in a man, during 24 hours, is equal to
8lbs. and 36 gr. and Mr. Abernethy, by a series
of experiments on himself, which he conducted
with the greatest patience and perspicuity,
concludes, that the quantity of liquid
matter perspired from the skin, in the same
given time, amounts to about two pounds
PROCESS OF GASSI.FICATION. 19S
and a half, and of air neatly three gallons*
On exposing the air to the usual tests, in order
to ascertain its quality, two thirds were
found to consist of carbonic acid gas, and the
remainder of nitrogen. If a mass such as this,
is produced by one individual only, during so
short a period, how immense must be the quantity,
which is generated by the whole human
race, as well as by the infinite multitude of
animals, and of vegetables, with which the
world is inhabited. The quantity of gaseous
matter, which is thus produced by animated
beings in their living state, it is probable, falls
far short, of that which is generated after
the actions of life are at an end, and after
dissolution is produced by the processes
of putrefaction and of fermentation* By allowing
the process of decomposition to take
place, in close and confined situations, a
facility is thereby afforded of collecting the
product, and of ascertaining the separate
nature of each. When the gaseous matter
which animals receive for the support of life,
during the process of inspiration, is compared
with that which is given out by the
process of expiration, the one is found to
be totally different from the other; a conclusive
proof, that it is owing to a change
which has taken place within the system,
by means of which these new properties
o
194 PROCESS Ot CLASSIFICATION.
have been acquired, during the act of incorporation
with it ; so that the system ought to be
considered the base, which gives the gas its particular
character.
Although the base from whence these gases
originate, is evidently to be referred to matter
solid or liquid, and that it is the specific
quality of the base which gives the
distinguishing character to each gas ; it is,
nevertheless, certain, that the convertibility
of the base to a gaseous state, whether it
be of a solid or liquid kind, is accomplished
by a power separate and distinct from any
inherent power resident in the base itself. We
have direct evidence, that not only animal and
yegetable matter, both solid and fluid, that
metallic oxydes, as well as the pure metal itself;
m short, that matter the most dense and solid,
of which we have any knowledge, in common
with water itself, is often converted to a gaseous
state. This change which the different
substances have undergone, which subserve to
this process, is total and complete, and no traces
whatever of the original base can be afterwards
detected.
From the concurrent evidence of our best
chemists, it may be stated, as far as chemical
analysis can be depended on that the atmosphere
consists of 77-5 parts in one hundred, by
measure, of nitrogen gas 21 parts of oxygen,
PROCESS OF GASSIFICATION. 195
1-42 of a gaseous vapor 0-&-0 of carbonic
acid gas besides a small proportion of hydrogen
gas. An analysis, such as this, is evidently
defective and imperfect ; MURRAY, therefore;
in his valuable chemical Work, very properly
rectifies this error, by defining the atmosphere
to be ” that mass of invisible and elastic fluid,
which surrounds the earth, to a great height
diminishing in density, as it recedes from the
surface, and may be regarded as a collection of
those substances, which are capable of existing,
in the aeriform state, at the medium temperature
of the globe; and which are constantly
disengaged, more or less abundantly, by the
processes going on, at the surface of the earth :
these, mixed with the substances which
they hold in solution with the water, constantly
evaporating from the surface with the
effluvia from animals and vegetables with
particles of common matter, in a state of extreme
mechanical division, and with the magnetic
and elastic fluids, light and caloric,
form a vast mixture, the composition of which
it is impossible, apparently, to determine with
accuracy.”
It must be acknowledged to be a matter of
astonishment, that the infinite variety of bodies,
both animal, vegetable, and common, which
subserve to this process, should be, ultimately,
so completely decomposed and dissolved, that
o2
PROCESS OF GASSIFICATION.
they are very seldom, if ever, reproduced, so as
to be discoverable by the nicest chemical test.
Mr. DALTON, in a place where 200 people had
been collected together, for two hours, could
only detect one part in 100 of carbonic acid
gas, and no hydrogen gas whatever, although
a quantity of both gases, must have been
given out during that period from the skin, and
lungs, of the whole assembly present.
Dr. PRIESTLEY found thatthe air of places the
most offensive and unhealthy, afforded as much
pure air, (oxygen) as that of others of an opposite
description ; the air of crouded cities of
low damp situations, or of confined manufactories,
was not less pure than the air existing in
the most open and champaign country: the nauseous
quality of the air, appearing not so much
to depend on any deficiency of oxygen air, as
on the presence of effluvia, not discoverable by
chemical means ; but which were, nevertheless,
made sensible by the sense of suffocation, and
oppression, which was felt by the persons present.
Mr. DAVY found, by analysis, that the air
from the river Senegal, in Africa, possessed
qualities precisely the same as the air of Hammersmith,
near London. BERTHOLLET ascertained,
that the air of Egypt, was like the air of
France: and Mr. CAVENDISH, likewise, found
that the air of various places yielded the same
products. DE MARTI, by experiments in
PROCESS OF GASSIFICATION. 197
Spain, obtained precisely the same materials,
and ascertained, that the atmosphere uniformly
preserved the same composition, whether with
regard to temperature to pressure, as indicated
by the barometer to winds to humidity
to the season of the year, or hour of the
day and night. GAY-LUSAC proved, by direct
experiment, that the different strata of the atmosphere,
contain the same gases, in the same
relative proportion. He filled a glass balloon,
at the elevation of 2173, and it was found to
contain, of oxygen 21-49 in 1000 parts; the
remainder was nitrogen. The atmosphere at
the surface, was analysed also at the same time,
in the eudiometer. The ABBE FONTANA, who
jnade a number of accurate experiments on the
quality of the atmosphere, in different situations,
says, that he found the air of one country,
and that of another, much more alike than
is generally believed. At Paris, he examined
the air of different places, at the same time, and
more especially of those places, in which it was
most probable to meet with infected air, be*
cause those places abounded with putrid and
impure exhalations ; but the difference did not
amount to one fiftieth of the whole. Having
taken the air from the top of a mountain,
near Paris, at the height of five hundred
feet from the plain, and compared it with the
air of Paris, taken at the same time ; after
198 PROCESS OF GASSIFICATION.
having subjected both to the same examination,
he did not find the former 1-30 better than the
latter. He also took the air from the upper gallery
of St. Paul’s cupola, which is 313 feet from
the base, and that of the stone gallery, which is
202 feet below the other, and comparing these
with the air of the adjoining street, he was not
able to detect any sensible difference between
them.
Although the correspondence which exists
between their various parts, tends to show, that
there is a considerable degree of uniformity in
the constituent materials of the atmosphere;
they, nevertheless, prove the imperfect condition
of chemical analysis also, and how inadequate
are the means which are employed, to
the attainment of the end. In the analysis
which is presented to us, neither the matter of
light, nor of fire, of color, nor of odor, are de*-
tected, or noticed,- but which are, nevertheless,
obvious and sensible to our organs of sense ;
the striking and astonishing effects which are
produced on the lungs, during the process of
respiration from the air of different situations,
prove, in a manner, the most decisive, that,
notwithstanding the supposed accuracy of
chemical analysis, an extreme degree of difference
does exist in the constituent materials of
which the atmosphere, of different places, is
composed.
HAPTER X.
jQN THE MECHANICAL PROPERTIES OF AIR IJf
JGENERAL, AND OF THE ATMOSPHERE 1^ ,
PARTICULAR.
SECTION I.
On the Power of Gaseous Matter to expand
equally in every direction.
As it was not my intention to extend the
observations I had to make, in describing the
different means by which gases are obtained,
the particular sources from whence they originate,
or the materials of which they are composed
; much less to enter into a detail of the
qualities they severally possess, or the various
changes which they undergo by chemical union
and combination, I shall proceed to explain
the physical properties which in them are inherent
and essential; and the mechanical efeffects
on other bodies, which those properties
are capable of producing.
200 PROPERTIES OF AIR
Such is the subtilty and invisibility of gaseous
bodies, that like the solar rays, their
materiality, for a long time, was disputed.
That they possess, however, the essential property
common to all matter ; that they possess
extension, or the occupation of space, is decidedly
proved, by the resistance which they oppose
to bodies moving through them, as well as
the power which they possess of excluding
other bodies, from occupying the same medium,
in which they are situated. If any hollow
vessel full of air, as for instance, a common
glass tumbler, be inverted on the surface of
any liquor, and immersed in it, the resistance
which the air opposes to the pressure of the
water, prevents the water from entering into
it beyond a certain point. If the air in the
glass be either condensed, into a smaller volume,
or entirely exhausted out of it; instead
ef the water preserving the same level which it
did before, it immediately rushes in and fills the
space which the air had occupied. Independently
of this universal attribute which air.
possesses, in common with every other species
of matter, it has properties of its own, by which
it is essentially known to be what it really is
and through which it is distinguished from
every other substance. Air is distinguished
from liquids, as well as from solids, by the
jtenuity and transparency of its parts;. and it
AND THE ATMOSPHERE. 20J
more especially obtains a generic character, by
the expansible power which it essentially contains.
That air possesses this expansible
power, is familiarly known to every tyro in
physical science. In order to prove it, I shall
have less necessity to add new facts to old
principles, than to give new principles to old
facts.
Although various external circumstances frequently
tend to direct this expansive power
into different channels ; whenever, air is situated
in space free and unconfined its expansibility^
acts equally in every direction, radiating,
as it were, from a centre, it becomes
extended to the whole circumference; so that
if a small portion of air be enclosed within a
bladder, and placed under the receiver of an
air-pump, the expansive power which the air
jn the bladder possesses, is found gradually to
dilate, in proportion as the air external to\the
bladder, in the receiver, becomes diminished.
The expansive power of air, in every direction,
is equally proved by the recoil and bursting of
a cannon, when the air in it is too closely compressed
; as it is, by the spherical appearance,
which every air bubble assumes. It is by
virtue of this particular attribute, that every
portion of air is in equilibrio with the whole ;
that it has as much the power of rising as of
falling that it possesses as much of levity, as
202 PROPERTIES OF AIR
‘
of apparent gravity as much the power ojr
pressing bodies upwards as downwards, of
ascending into the nostrils, as descending into
the lungs ; that a small portion of air, separated
by the thinnest covering possible, from a
larger column, suffers no additional pressure ;
that the back of my hand sustains no more
pressure from the large column above, than the
palm from the small portion of air below it;
that we feel no weight that we suffer no violence
that we are exposed to no danger :
that, in fact, the equable pressure of the air,
in every direction, under the same circumstances
of external influence, is no more capable
of smashing our bodies to a cake, than it is
of bursting the parietes, or sides, of the thinnest
air-bubble that can be conceived.*1
* I might produce, without end, facts to prove this particular
attribute. The expansible power of air in every direction
is further proved, by putting a piece of lead to the
mouth of a syringe, and abstracting the air out of it ; the expansible
force of the external air, is found capable of keeping
the lead in forcible contact with the mouth of the syringe, in
whatever direction the weight may be situated. It is the case
with two hemispheres, when the air has been exhausted out
of them, &c. It is the case with a bladder placed upon an
exhausted receiver : it will burst with as much facility downwards,
sideways, and upwards, &c.
AND THE ATMOSPHERE. 203
SECTION II.
On the Equilibrium of Liquids and Solids.
THIS state of equilibrium, or of balance, is not
confined to gases only ; it more especially extends
to homogeneous bodies in general, whether
they be of a liquid, or of a solid kind.
Before the inquiry is entered into, it should
be clearly understood, that I take the natural
condition of bodies, that state of them
in which they are found to be in a common
state, as presented to us by nature, as the
principles from whence I proceed ; and that
wherever bodies are made to change their natural
state, by the operation of external causes,
that change is ever to be considered as
forced, and unnatural. The difference which
exists between a condition which is natural,
and unnatural, between the existence of any
substance in a condition which is natural, and
common to it ; and that which is artificial, and
forced, is so apparent to commonsense, that I
should not have deemed any illustration necessary
of the difference which exists between
them, had not the false philosophy of the present
day, inverted the order of things, and mistaken
the one for the other. In order to render
204 PROPERTIES OF AIR
the subject more clear, I shall give JOHNSON’S
definition of both.
” NATURAL,” produced, or effected, by nature
not artificial bestowed by nature, not
acquired not forced not far fetched: dictated
by nature following the stated course of
things.”
” UNNATURALS, contrary to the laws of nature
contrary to the common instincts forced ;
not agreeable to the real state of things ; not
representing nature.”
- That in the system of nature, every substance
which exists in it, is characterised by
particular attributes, which belong, and are
natural to it; and which distinguish it from
every thing else, is an incontrovertible truth*
It is these attributes that constitute the materials
on which definition is founded : thus it is,
that mens sana in corpore sano, a sound mind
in a sound body, constitutes the natural condition
of the human race ; mens insana in corpore
insano, an insane mind in a diseased body, it*
unnatural condition. It is the natural condition
for a man to stand upon his feet unnatural
for him to rest upon his head ; natural for him
to have his arms at liberty unnatural for him
to be confined in a straight waistcoat ; natural
for the different species, to have -certain deter-^
minate complexions, and forms unnatural for
AND THE ATMOSPHERE. 205
the individuals, to have the ane superseded and
obliterated, by external coloring, or the other
mutilated and defaced.
- It is natural for air to exist in spaces free,
and unconfined it is unnatural for it to be
confined in close vessels, and thereby prevented
from exerting the essential and natural power
it contains, of expanding, equally, in every direction.
- It is natural for water to subsist, in a liquid
state ; it is unnatural for it to be changed
by the operation of an external cause, either
into a gaseous, or into a solid one ; and more
especially it may be considered to subsist in an
unnatural state, when it has been acted upon,
by the living principle of animals and vegeta- ,
bles, and incorporated writh them. Under circumstances
such as these, wrater must be considered
as having lost its original properties, insomuch
that the definitions by which it was
characterised are altogether lost ; and, consequently,
that it then subsists in an unnatural
State. Whatever may be the natural and primitive
condition of water, whether it be of a
solid kind, as some individuals suppose or
that of a liquid, as is most probable -is of no
consequence with respect to the matter at issue.
Whatever change it suffers from its original
state, whether it be from a fluid into a solid, or
from a solid to a fluid one, must ever be consi206
PROPERTIES OF AIR
dered a change from better to worse. Without
dwelling upon this particular point, I shall
proceed to show, that the particles of which
liquid water is composed, in common with
those of liquids in general, with relation to each
other, subsist in a state of equilibrium, provided
those particles are of equal density.
The pressure upon the upper part is the same
as the pressure on the under one, as well as
from side to side.
If in a column of water, or any other liquid,
the particle 2 presses upwards upon the particle
1, as much as the particle 1 presses upon
the particle 2 ; and the particle 2 presses upon
the particle 3, as much as the particle 3 presses
upon the particle 2 ; and so on to an indefinite
series : then must it follow, that all the united
particles by pressing, as much as they are
pressed ; and resisting, as much as they are
resisted, subsist, with respect to each other,
in a state of perfect equilibrium. If the pressure
is equal in the particles of which a column
of water is composed, then must it follow, that
the pressure of the whole column must be
equal also. If it were otherwise, if the pressure
at the bottom, was the sum of the particles
altogether, in a regular and increasing
series, the whole would be different from the
parts. The pressure of the fluid would, in
that case, be less upwards and sideways, than
AND THE ATMOSPHERE. 207
it would be perpendicularly downwards. So
far, however, from the assertion being founded
in truth, that the pressure of water in water,
or of liquids in liquids, of equal density, is in
proportion to their perpendicular heights ; I
maintain on the contrary, that this proposition
which is so universally received as true, and
which constitutes the fundamental principle of
hydrostatic science, is altogether unfounded.
I shall not detail the experiments which are
generally used to show the equal pressure of
fluids in every direction, as they are familiarly
known to every one who has attended a single
lecture on hydrostatics ; but shall rather appeal
to the evidence of common phenomena,
as they present themselves to our observation.
We shall then find, that bodies placed at the
bottom of a column of water, suffer no more
pressure, than when they are immediately below
the upper surface of it ; and that instead of
suffering any alteration in figure, or in form,
by the increased pressure, which it is erroneously
supposed they undergo, that they continue
uniformly the same, in whatever portion
of the column they may be placed. The most
brittle bodies are often immersed at a depth the
most profound, and exposed to this supposed
pressure without cracking the most flexible
without bendingthe most expansible without
bursting. An egg, which would be broken
208 PROPERTIES OF AIR
and smashed under the pressure of two cubic
inches of lead, will remain in the sea, at the
depth of thirty fathoms, as entire and perfect
as the most solid body. The finest fibril
of the finest blade of grass, which grows
at the bottom of the ocean, is found to wave
and to float, erect and rigid, under this immense
column of water, without suffering
more pressure from it, than the grass of the
field does from the medium of air in which it is
involved. This fact is more especially illustrated,
by the perfect and entire manner in
which the leaves of corals, and of corallines,
are preserved at the greatest depths.
Immense forests of these vegetables are to be
seen, in the Indian seas; and, although the
fibres of which their foliage is composed, become
hard and firm, by exposure to the air ;
they break by the slightest touch, when they
are first taken out of the water; and yet they remain
in it, without Isesion, or violence, at the
depth of 10 and 15 fathoms from the surface.
If the assertion, which is so universally received
were true, that the pressure of water,
was in proportion to its perpendicular height
is it possible, I would ask, for any human being,
to support the pressure to which lie is often
exposed, in consequence of .being immersed
in it. The facts are so numerous and common,
AND THE ATMOSPHERE. 209
that it is almost unnecessary for me to mention
them. Having been favored with an answer
to some inquiries which I have made
upon this subject, from CAPT. HORSBURGH, a
man of the greatest veracity, and who has had
the best opportunity of accurate observation,
having navigated the Indian seas for 27 years,
I shall give an extract of his letter to me.
” I cannot give you any particulars relative
to the length of time divers can remain submerged,
from actual experience, excepting the
following instance. I was an officer of the
Gunjavar, a large ship belonging to Surat, in
1787, and being disabled, by a storm, in the
China sea, we took shelter in Galong Bay, at
the island of Hainan, which fronts the Gulf of
Tonqeen. When about to sail from thence,
our cable parted close to the anchor, in endeavouring
to weigh it ; and we got two fishermen,
who went down, and fixed a hawser to the anchor,
which lay in 11 fathoms water. These
men swam from the surface to the bottom, by
bodily strength, without any weight affixed to
them, in order to help their descent, and they
swam down alternately, to relieve each other
in the work they undertook, until it was completed
; by which we recovered the anchor.
Each of them went down about four or five
times, in the depth of 11 fathoms, and were
about two minutes under water, as near as I
p
210 PROl-EKTIES OF AIR
could judge, not having a watch upon me at
the time. I certainly did not believe it possible
for men to swim perpendicularly downwards
to the depth of 11 fathoms, and execute
a laborious task there, until I witnessed this
undertaking.
” I have heard it said, that the pearl divers,
in the Gulf of Persia, descend into depths of
30 or 35 fathoms, to procure the oysters, by
means of a heavy stone fixed to their feet by a
strap ; as soon as they reach the bottom, they
shake the stone clear of their feet, and gather
the oysters into a bag they have for that purpose;
and when they want to ascend, they
pull a cord which is connected with the boat,
or vessel, and they are immediately drawn up,
very speedily, by the persons stationed for that
purpose,”
If we, therefore, admit the estimate which is
generally made, that a cubic foot of water
weighs 64 Ib. and that a man at the bottom of
the sea, at the depth of 30 fathoms, exposes two
square feet of the surface of his body to the perpendicular
pressure of the column of water ; it
will be found, that by multiplying 180, the number
of feet, by 128, the number of pounds ; that
he must have sustained a pressure equal to
21-600 Ib. I shall not attempt to show the folly
of such a conclusion by any further detail. If
AND THE ATMOSPHERE. 211
more evidence were wanting to show that the
pressure of water is not according to its perpendicular
height, I would appeal to the hydrostatic
balance. When a substance of any
given magnitude is placed in the pan, which is
suspended in the air, it will balance the substance
in the pan under the surface of the water ;
the weight of the substance in the water, does
not increase in proportion to the depth of the
water in which it is immersed. The same
quantity of matter in the scale, which is placed
and suspended in the air, will balance the matter
in the one which is situated under the surface
of the water, as perfectly at the depth of fifty
fathoms, as it will do at the depth of one. The
pressure at the bottom, therefore, is not greater
than it is near the top. The pressure of the water
upon the under part of the scale, is exactly the
same, as the pressure upon the upper part of it ;
and by being pressed equally in every direction,
it remains suspended, and balanced, in
whatever part of the water it is situated. Notwithstanding
these most obvious truths, the
principles on which the science of hydrostatics
depends, are in direct violation of them. I
cannot expose the error of these principles
more effectually, than by quoting them as
they are expressed by authors and teachers
in general.
212 PROPERTIES OF AIR
Proposition 1 . Any part ofafluid at rest, presses
and is pressed equally in every direction.
Proposition 2. When the surface of a fluid
is level, the whole mass will be at rest.
Proposition 3. The weight of fluids is as
their quantities of matter.
It is proper for me to observe, that I have
placed these fundamental propositions in the
order which they ought scientifically to be
placed, and, for that purpose, have inverted the
mannerin which theyare generally placed,which
is as follows :
Prop. 1. The weight of fluids, is as their
quantities of matter.
Prop. 2. When the surface of a fluid is level,
the whole mass will be at rest.
Prop. 3. Any part of a fluid at rest, presses
and is pressed equally in every direction.
Although these propositions are laid down
as fundamental principles, and the truth of
them is attempted to be proved, with all the
display of mathematical demonstration, I, nevertheless,
contend, that whoever compares the
first and the third together, will be immediately
compelled to acknowledge, that they are altogether
at variance with each other. If the
pressure or weight of fluids, is in proportion to
the perpendicular height, or altitude thereof;
or to their quantities of matter ; how are these
assertions, I would ask, to be reconciled with
AND THE ATMOSPHERE. 213
the other proposition, which immediately follows
; namely, that the pressure offluids upwards,
is equal to the pressure downwards, at any given
depth ; and that when the mass is level, the
whole mass will be at rest ; and that any part
of a fluid at rest, presses and is pressed equally
in all directions ? The equable pressure of
fluids in all directions, is proved by a very simple
diagram, which being generally advanced
by the supporters of these contradictory opinions,
will, perhaps, be better understood by
them, than if it were one of my own. ” Let
- B. C. D. be a vessel of water, whose altitude
- F. is supposed to consist of a column of
10, or 10,000, aqueous particles; then it is
evident, the first, or uppermost, particle 1.
can affect the next particle 2. only by its pressure
every way, which, therefore, is as 1. and
since the particle 2. is immoveable, and action
and reaction are equal and contrary ; the said
particle 2. will resist upwards upon the particle
- with a force which is as 1; and it must evidently
appear, that what holds good with respect to
these, must hold good also with respect to all
the rest, in an indefinite series.”
In order, however, to reconcile contradictory
* I quote the words of others, and, therefore, am not answerable
for the folly of ascribing action and reaction to bodies,
which are stated to be immoveable.
214 PROPERTIES OF AIR
propositions by mathematical demonstration,
false conclusions are drawn in violation of the
demonstration itself; after stating it as an
evident truth, that the particle 1. can affect the
next particle 2. only by the pressure every
way; which, therefore, is as 1. and the particle
- will react upwards upon the particle
- with a force which is as 1. it is then
falsely asserted, that the particle 2. acts
on the particle 3. by pressure doivnivards with
two degrees of force, arising from its own
weight, and that of the particle above it. So
far, however, from this conclusion being justified
by the fact, facts universal falsify the
conclusion. I will maintain it as an undeniable
and universal truth, that opposing forces equally
balanced, destroy each other, wholly and totally
; that not only if a body is acted upon by
three forces, which are proportional to, and in
the direction of, the three sides of a triangle,
the body will be kept at rest ; but that it will
be more especially the case, if these forces act
equally from a centre, towards the whole of
the circumference, or vice versa. If, for example,
four powers, of whatever description they
may be, (whether they be four weights, four
levers, or four elephants,) exert equal force
in opposite and contrary directions, the effect
of the whole is absolutely lost, by the separate
power of each. If equal bulks of matter, whose
AND THE ATMOSPHERE. 215
densities^ are equal, \vhether they consist of
one cubic inch, or of the whole nucleus of the
earth, were put in opposite scales ; so long
as they were of equal magnitude, and of equal
densities, they would subsist in a state of equilibrium,
or of balance. In like manner, it is by
the pressure of water, equally in every direction,
that it produces no pressure in any ^particular
direction. It appears that the pressure produced
on bodies immersed in fluids, at different depths,
is the same; as well as the pressure of fluids,
of equal densities, upon each other ; it must
follow, then, that the fundamental proposition
in hydrostatics, which affirms, that the weight
of fluids is in proportion to their base, and perpendicular
height, is an erroneous one. It
ought, on the contrary, to be affirmed, that the
pressure of water in water, as well as of all
fluids of the same degree of density, when they
are immersed together, instead of pressing unequally
downwards, press equally sideways and
upwards.
The different experiments which are advanced
for the purpose of showing the weight
of water in water, are nothing more than so
many false facts, which only prove the density
of water with relation to the rarity of air ; or
the comparative gravity of the one, with respect
to the levity of the other. ” If a stopped phial
be suspended from an arm of a balance, in a
216 PROPERTIES OF AIR
vessel of water, and balanced by weights from
the opposite arm of the balance : upon unstopping
the phial under water, a quantity of water
will rush into it, by which the weight will be increased,
as much as the weight of the water in
the phial.” From this effect, which is thus produced,
the sinking of the bottle, when water is
substituted in it for air, it is immediately inferred,
as if demonstratively proved, that the parts of
water retain and possess their weight and gravity
in water. If the different parts are examined
which are concerned in constituting this
experimental fact the conclusion which is
drawn from it, will be found one of the most
fallacious that can be conceived; the parts
must be separated, and separately examined,
in order to show the error of the whole.
If four cubic inches of copper are immersed
in Mater, such is the density of the copper, with
relation to the rarity of the four cubic inches of
water, which the copper has displaced, that
the copper presses downwards is heavy, and
sinks to the bottom; if these four cubic inches of
copper, are beaten out into the form of a bottle,
and filled with water, the same consequences
will ensue ; although the copper bottle, filled
with water, will sink, it will not sink so rapidly
as the cubic inches of copper in a solid form
because the increased magnitude which the
copper has acquired in the change which it
AND THE ATMOSPHERE. 217
has undergone, from the cube, to the form of a
bottle, diminishes its weight in proportion to
tiie increased quantity of water which it has
displaced ; the excess of density contained by
the copper, over the water in which it is immersed,
will, nevertheless, cause the bottle to
sink. The pressure downward which is thus
produced, is not the pressure from the increased
density of the water in the bottle above that
which is external to it, both are of the same
nature: the difference altogether depends on
the difference which exists between the pressure
from the copper, overcoming the resistance
of the water. The denser body immersed
in the rarer one. If to the top of this bottle of
water, thus sinking in water, a bladder full of
air is tied to the neck of it, instead of the bottle
of water sinking as before, it will be found to
float, and to rise^on the surface the reason is
obvious ; the rarity of the air in the bladder,
together with the density of the copper, are
not equal to the density of the water alone, in.
which the bottle is placed : when a bottle of
water sinks in water, and a bottle of air swims
in it, it is not that water gravitates in water ;
but that the solid substance of which the
bottle is composed, is denser than the water
in which it is immersed ; and when a bottle of
air floats in water, it is because the air which
that bottle contains, added to the weight of the
218 PROPERTIES OF AI&
bottle, are together rarer, and consequently
lighter, than the density of the water which
they have displaced ; or, in other words, the
bottle swims by the levity of air ; it sinks by
the excess of weight in the bottle ; instead,
therefore, of proving the gravity of water in
water, it only goes to prove, that water is denser,
and consequently heavier, than air ; and
more especially than of the rarified medium
which remains after the denser parts have
been exhausted out of the bottle.
If the parts of water retained their gravity in
water, the different propositions on which hydrostatics
are founded, would be altogether
violated; instead of the different parts of a
fluid mass, being as much pressed as they are
pressing, equally in every direction, the different
parts of that fluid would press in a particular
one ; instead of the whole mass of a
fluid being at rest, when the surface of it is
level. Instead of this state of equilibrium of
equality of pressure on every direction, the
pressure of fluids would in that case be as their
quantities of matter, the pressure which they
produced would be the pressure of weight of
weight perpendicularly downwards, not sideways,
or upwards. If the weight of water increased
in proportion to its quantity, whether
of length or of breadth, or of both together, the
pressure of weight which it would occasion,
AND THE ATMOSPHERE.
would be correspondent to its perpendicular
height ; it would be similar to the pressure of
- block of lead, in water, or in air, at the centre
of gravity. The weight of the water would
prevent a diver from rising to the surface, as
well a& a piece of cork, or a bubble of air.
We may, therefore, conclude, that the pressure
which fluids oppose to bodies, is not the pressure
of weight ; and, consequently, that the
proposition is an erroneous one, which asserts,
” that the pressure of fluids is proportional to
the base, and the perpendicular height of that
fluid, whatever may be the form of the vessel,
or quantity of the fluid.”
It may, indeed, be stated as a corollary
from the demonstration above named, that the
pressure upon all the particles of the fluid, at
the same depth, is equal in every part, or, in
other words, the particles of fluids, at the same
depth, press each other every way, and in all
directions equally ; if this were not the case, it
is very justly observed, that if any particle of
a fluid were pressed in one part, more than it is
in another, it must give way, or yield, till the
pressure becomes every way equal ; otherwise
an incessant intestine motion of the particles
would ensue ; which is absurd, and contrary to
all experience. The particles, I maintain,
would press downwards, or sideways, as they
are found to do, when a hole is made in the
220 PROPERTIES OF AIR
bottom, or side, of a vessel full of water, or any
other fluid, immersed in a medium rarer than
the fluid which the vessel contained ; whenever
this is the case, the fluid presses more than it is
resisted, the degree of pressure depending on
the degree of difference which exists between
the density of the fluid within, and the rarity
of the fluid without : hence we find that water
which existed in equilibrio in water without
weight, in air has weight ; pressing downwards
upon the air, more than it is resisted upwards
by the air. These effects flowing from the same
principle, are observable, when fluids of different
densities are immersed together. Whenever
they do not chemically combine together,
they diffuse, and separate themselves into
different strata ; the denser falling, or sinking,
to the bottom ; and the rarer rising to the top,
in a regular and graduated manner. The
pressure, under these circumstances, is not
equal in every direction among the particles
of the whole mass ; the pressure downwards
is greater than the pressure upwards ; and a
vessel immersed in and balanced by the liquid,
would be carried down with it to the bottom of
the vessel.
The errors, on this subject, which now prevail,
appear to me to arise from subjecting to
the same laws, solids and fluids together ; bodies
whose nature and properties are altogether
AND THE ATMOSPHERE. 221
different from each other. Nothing, perhaps,
can more distinctly prove the differences which
exists in the principles on which the phenomena
of each depend, than the change which
takes place in those phenomena, either when a
liquid is converted into a fluid, or when a fluid
is converted into a solid. If a portion of
water, for example, is converted, by the process
of refrigeration, into a solid fprm, and
consolidated into ice; instead of pressing
equally in every direction, it presses in a particular
one only ; the weight of the whole mass
is concentrated into one point at the bottom,
which point is called the centre ofgravity. If
a block of lead, of any dimensions, say ten feet
square, be divided by ten lines, and immersed
in any medium rarer than itself; the pressure
of the lead, instead of extending, like the pressure
of water, equally in every direction, will
be entirely limited and confined, towards the
centre of gravity, at the bottom ; and the
weight, or pressure downwards, will then be
equal to the sum total of all the parts ; but if
the solid lead be liquified, it will, like the ice,
after it has been melted, press like other liquids,
equally every way.
The observations which I have made on
the state of equilibrium, in which the different
particles of fluids, of equal densities,
exist, with relation to each other, more especi222
PROPERTIES OF AIR
ally refer to solids in general ; to solids whose
densities are altogether equal. The particles
of which a mass of granite is composed,
with relation to each other, press as
much as they are pressed ; they resist, as
much as they are resisted ; and, therefore, virtually,
suffer no pressure; they subsist in a
state of equilibrium, or of balance. By being
incompressible in their nature, solids do not,,
because they cannot, suffer any compression.
The incompressibility of water, has been satisfactorily
proved, by the florentine experiment :
a volume of it was enclosed in a golden sphere,
and placed between two screws, and acted
upon by the most powerful agents : although
particles of the water issued through the gold,
and proved that it was porous ; it, nevertheless,
showed that water was incompressible ; and
that its bulk could not be diminished, by the
compressing force to which it was exposed.*
If liquids are in their nature incompressible,
* It ought, however, to be mentioned, that as water has,
generally, a given quantity of air diffused in it, and which
is compressible to a great degree, so as to be reducible from
a large to a smaller volume ; that whenever the experiment
has been made, and an opposite effect produced, we ought
to conclude that the small diminution of bulk which has taken
place, has, most probably, arisen from the condensation of
the air, in consequence of the compression to which it has
been exposed, and not from the condensation of the water.
AND THE ATMOSPHERE. 223
how much more is the attribute likely to belong
to those bodies which are essentially hard and
solid, whose natural tendency is to remain in a
quiescent and passive state; and which offer
resistance alone to the power by which they
are assailed.
In describing, therefore, the phenomena ofnature,
and in tracing those phenomena to their
producing causes, we must ever take things as
they subsist in their natural state. We must consider
the system ofnature, to be a system founded
in symmetry, and in order ; and which is
governed by general laws, that these laws are
all subservient to the preservation of this economy
; and that the objects dependent on this
economy are the elements, and that these elements
proceed from the most minute and active,
to the most dense and passive. The laws,
therefore, by v/hich the different elements of
which the universe is constituted are governed,
are totally different from each other ; this distinction
arises from the difference which subsists
in the quality of the matter of which they
are composed, and of the use for which they are
designed. Although it is very true, that these
elements are for the most part, at present, combined
and united ; there can be no doubt, that
they are the sources from whence the parts
proceed ; and that the laws by which the parts
are governed, are constantly exerted in order
224 PROPERTIES OF AIR
to preserve, and to restore, the symmetry and
gradation of the whole. It would seem to be
with a view to this end, that we behold the
various species of dead and of common matter,
of which the universe is constituted, obeying
certain rules of rest, or of motion, according
to the class to which it especially belongs,
and of returning to their particular elements
after they have been separated from it. Whether
it be solid, liquid, or gaseous matter
; whether it subsist by itself, or be integrated
and incorporated into other masses, it
obeys that universal law of nature, of obtaining
and preserving its proper level. It is in
obedience to these laws that solids, when they
are placed in media rarer than themselves,
gravitate and fall ; that water, elevated in
the air, above the surface of the ocean, flows
back into it; that fire, and gaseous bodies,
which are permanently elastic and expansible,
float on the surface of both. However this
tendency of preserving its proper level, may
be suspended, by the operation of external
causes, it, nevertheless, continues immutably
the same, and constitutes the vis insita, or
natural tendency which pervades every particle
of the material world. I shall, therefore,
proceed to detail the effects which are
produced, by different bodies, whenever this
state of order, and of subordination, is inverted
and destroyed.
, /CHAPTER X
ON THE GRAVITY AND LEVITY OF SOLIDS ANX>
LIQUIDS.
WHENEVER there subsists a difference in the
quantity of matter, which any body contains
within a given bulk, with relation to the quantity
of matter which it displaces the state of
equilibrium, or of balance, becomes destroyed
; instead of such a mass of matter, remaining
suspended in equilibrio, it either rises or
falls ; the weight, or pressure, downwards, is the
measure of the difference which exists between
the density of the one, and the rarity of the
other : and, on the contrary, the levity or
pressure upwards, is the test of the rarity of
the one, with respect to the density of the
other.
If a body contains as much matter as it displaces,
it remains suspended and balanced;
Q
226 GRAVITY AND LEVITY
if it contains more matter than it displaces, it
falls ; if less, it rises ; it is not to the body
alone, or to the medium alone, to which these
effects are to be ascribed, but to the mutual
relation which exists between the one and the
other. The natural measure, or test, which
exists of the different quantities of matter in
different bodies, is ascertained by the different
degrees of pressure downwards which they
produce ; so the pressure upwards of different
bodies, is the test of the comparative
degrees of rarity in the particles of matter, contained
within the same bulk, with relation to
the density of the particles of matter by which
they are surrounded. Bodies such as these,
instead of remaining suspended in equilibrio,
instead of pressing downwards, are found uniformly
to press upwards, and to rise, with a
force which is equal to the difference which
exists between the rarity of the materials of
which they are composed, and the density
of the matter in which they are immersed:
it is from this cause, that bodies are lighter
in a dense, than in a rare medium; and
heavier in a rare, than in a dense one ;
why they are lighter in quicksilver, than in
water ; in water, than in air ; lighter near the
surface of the earth, than in the most elevated
regions of the air ; and, finally, lighter in a
Receiver full of atmospheric afr, than in an
OF SOLIDS AND LIQUIDS. 227
exhausted one. Air, therefore,, confined in
close vessels, whose solid sides fraye the power
to restrain, and to subdue its expansive force,
weighed in ai> exhausted medium, will be
found more ponderable, than the same bulfe pf
air rarified ; and air rarified, more poiiderar
ble than the subtile and residuary matter, left
in the exhausted receiver ; for, however complete
the exhaustion of the air in the receiver
may appear, it, nevertheless, continues always
to he a plenum a plenum of air, dilated to the
extreme., which no instrument whatever can
exhaust.
The best air-pump that has ever been
constructed, can only exhaust the air it conr
tains, twelve hundred times its original bulk,-ran4
the Torrcellian tube, which is considered
the most perfect mode we possess of
abstracting air out of space, can never abstract
rays of light, more than of color, or of firer out
of it; or prevent them from flowing into it;
and by filling space, effectually prevent tjie
existence of a void,
I will not pretend to say, what might have
been the condition of things, at the beginning,
when the earth was without form, and void
5
or, as it probably might be better rendered,
when the earth was without form, when void,
and when darkness were on the face pf the
(Jeep. Certain, however, it is, that after Gad
Q2
226 GKAVITY AND LEVITY
said, Let there be light, and there was tight>
that not only the whole of the planetary spheres
was filled with that subtile matter, but with the
different bodies which it had acted upon, and
changed, from a solid and liquid, to a gaseous
and igneous state. Such is the essential attribute
which belongs to these different bodies,
of expanding and diffusing themselves, that the
plenitude of matter in space, is found to exist
every where, and a void no where : while extension
is the essential attribute of matter, so
space is the necessary recipient of it ; and as
matter cannot exist without space to contain
it, so space cannot subsist without matter to
fill it. Independently of supernatural means,
matter can no more be annihilated, than it can
be created ; it may be modified, and changed,
but it cannot be destroyed. However altered
in figure, and in form, the different secondary
qualities of matter may be, the substance itself
is not like the negative quantities in algebra,
that can be negatived into nothing ; and a vacuum
formed. To suppose that a perfect vacuum
can exist to suppose that a perfect
exhaustion, either subsists in nature, or can be
accomplished by artificial means, is to admit
the possibility of that which is impossible ; it
is to suppose space to be capable of existing by
itself, or in the abstract, without any necessity
for matter * to fill it. If such an incongruity ia
OF SOLIDS AND LIQUIDS. 22S
nature could be supposed capable of existing,
the bond of continuity, by which the different
particles of matter are held, and connected
together, would be separated and destroyed ;
instead of the universe in general, and this
world in particular, being intrinsically one
WHOLE ; it would, in such a case, consist of as
many distinct universes and worlds, as there are
.separated parts, or vacua ; and every vacuum
would, defacto, constitute one distinct world,
or one distinct universe. Until, therefore, such
a non-entity can be proved to have an actual
subsistence, the word vacuum, as typical and
expressive of an idea, without any prototype,
or exemplar whatever belonging to it, ought
to be blotted out of every dictionary, the
doctrine of absolute weight for ever abandoned,
and considered a positive absurdity, [t is from
principles such as these, that we are enabled
to understand the cause, why bodies in general,
(whether they be solid, liquid, or gaseous,) are
made to undergo a change from a state of equilibrium,
to a state of difference of levity, or of
gravity, according to the situation in which
they are placed.
As the doctrine of gravitation is intimately
connected with the subject I am about to discuss
; and as it is briefly, but clearly stated, by
the Rev. S. VINCE, Plumian Professor of Astronomy,
and Experimental Philosophy, at the
GRAVITY AND
^University of Cambridge, in a tract which ha
has published, with a view of accounting fofr
the causfc of gravitation, from mechanical
principles ; I shall take the liberty of making the
following extracts.
” KiEPlER supposes that the effect of attraction
Is produced by an immaterial image of the sun,
projected from the sun t6 the planet, and draw*
ing the planet towards the sun. He says,
” Effluxus igitur, quemadmodurn et lcis, imiriftteriatus
est ; non qualis odoriim cum dimi*
nutione substaniia?, non qualis ‘caloris ab ^estuante
fornace, et si quid est simile, quibus media
implentur. Relinquitur igitur, ut quemadmodum
lux, omnia terrena illustrans, species est
immateriata ignis illius, qui est in corpore solis:
ita virtus haec, planetarum corpora complexa
et vehen^, sit species immateriata ejus virtutis^
qiiae in ipso sole r^sidet, ineestihiabilis vigoris,
adeoqu actus primus omnis motus mundani.
Videri namque possit in corpore solis
latitare divinum quippiam, et comparand urn
animse nostrae, ex quo efluat species ista pla-t
netas circumagens, uti ex anima jaculantis
lapillos species motus in lapillis adhaerescitj
qua provehuntur illij etiam cum qui jaculatus
est manum ab illis reduxit.” (De Motibus
Stella Murtis.)” Etsi igitur species corporis
solariis attenuatur in longum et latum, non
minus quam lux videtur potius hoc sequen*
OF SOLIDS AND LIQUIDS. 231
tlum, effluere speciem immateriatam corporis
ipsius, cui specie! et vis prensandi, et lux, luci
vero et calor et color, quodlibet ex suo fonte
derivatum, inhaereant nee enim uspiam est
species ilia, nisi in opposite et occurrente corpore,
lucis quidem in ejus superficiei opaca ;
virtutis vero motrica in tota corpulentia : in
spatio vero interrnedio inter solera et superficiem,
non est, sed fuit.” (Epist. Astron.) It is
not here easy to annex any clear ideas to our
author’s meaning ; in what manner this immaterial
image of the sun acts upon the planet to
bring it towards the sun (vis prensandi) he has
not explained. He speaks of the cause as an
immaterial active body ; as a divine mind ; as
the mind of man ; and by its action retaining
the planets in their orbits.
” The only hypotheses which have met with
any advocates amongst philosophers, are those
of DES CAHTES, Sir I. NEWTON, and I. BERNOUILLI.
Des Cartes attempted to account
for the motions of the planets, by supposing
them to be carried round the sun in vortices.
But Sir I. Newton, besides his other arguments
against this theory, very justly observes,
that the free motioos of comets in all directions,
and their being subject to the same laws
which the planets are, destroy, at once, the
hypothesis of vortices. Sir I. Newton accounts
for gravitation in the following manner. He
$32 GRAVITY AND LEVITY
supposes that thetie is a fluid surrounding the
sunj which increases in density as it recedes
from the sun, and that u body put into this
fluid will be forced towards the sun by the difference
of the .pressures on the opposite sides.
- Bernoulli was dissatisfied with both these
hypotheses, and formed a system from the two,
(un juste milieu entre les deux m’a paru le plus
sur,) which he thinks will solve all the phenomena.
He supposes that there are two kinds
of vortices, one belonging to the sun, and the
other to the principal planets* He conceives
also, that there is a torrent which sets in continually
from the extremity of the vortex towards
the centre, causing thereby a tendency
of all the bodies in the vortex towards that
point ; and thus he accounts for the gravitation
of the planets to the sun. He further supposes
that there are two sorts of matter ; one, perfectly
fluid, without any elementary particles ;
without inertia ; and which gives no resistance
to bodies moving in it; the other formed of
corpuscles. These two matters are mixed together,
and form the vortex. When the vortex
first began to revolve, the particles of the second
kind of matter, receded a little from the centre,
and formed a vortex of different densities, and
thus there remained a space about the centre
of the vortex, filled with the first matter only,
and this is the matter which forms the sun. The
AND LIQUIDS. 233
matter of the sun being in an effervescent state,
small particles are thrown off, (as a steam from
boiling water,) and as these must act upon each
other, and upon the particles of the second”
kind of matter, many of them must constantly
be reflected back, and thus a current (a& before
mentioned) is continually setting in from the
extremity of the vortex towards the centre.
The particles thus thrown off, form both light
and heat. Such is the system, according to the
hypothesis of this author. But he sets out with
a supposition which can never be admitted, and
upon the truth of which his investigations depend
: that is, that the different parts of the
fluid, as it revolves about the sun, act upon
each other in proportion to their distances from
the sun, in the same manner as if they were
connected by an inflexible lever revolving about
the same centre.
” M. SAUSSURE accounts for attraction, by
supposing that all space is filled with particles
of matter, moving rapidly in all directions ; and
that the particles which fall on the opposite
sides of any two bodies, in lines parallel to the
line joining to their centres, will impel the bodies
towards each other, the sides next each
other not being so acted upon. But, in this
case, the moving force of each body would depend
on the surfaces of the bodies ; whereas it
ought to be as the quantity of matter in each
234 GRAVITY AND LEVITY
respectively. This consideration, therefore,
without entering into any further examination
of this hypothesis, is sufficient to show that it
cannot be admitted.
” The gravitation of a planet towards the sun
varies inversely* as the square of its distance
from the sun ; that is, whatever be the magnitude,
or density, of the planet, ite acceleration
towards the sun varies in that ratio. Whatever
cause, therefore, is assigned, it must satisfy
this law of variation.
” If we suppose material particles to emanate
from the sun, and ct upon the surface of the
planet, or to pervade the body and act upon
the whole of it, the tendency of such action, from
the known mechanical operations of bodies
upon each other, must be to drive the planet
from the sun. Such an emanation, therefore,
cannot be admitted as the cause of gravitation.
We will, therefore, next consider Sir I.
NEWTON’S hypothesis.
” If the sun and planets act upon each other,
it must be by some intermediate substance
which is invisible; this substance we must,
therefore, suppose to be an elastic fluid ; and
upon such a cause, Sir I. Newton attempts to
account for gravitation. In his second advertisement
to the second edition of his Optics, he
says,
” To show that I do not take gravity for
an essential property of bodies, I have added
OF SOLIDS AND LIQUIDS. 235
%rie question concerning its cause ; ch using to
propose it by way of a question, because I am
not yet satisfied with it for want of experiments.”
He, therefore, proposes (Optics, Quaery
21.) to account for the gravitation of the
planets towards the sun,
” By means of an
elastic fluid surrounding the sun (and in like
manner surrounding every other body,) suppo-^
sing this medium to increase in density, as it
passes at greater distance from the sun, causing
thereby the gravity of these greater bodies
towards each other, and of their parts towards
the bodies; every body endeavouring to go
from the denser parts of the medium towards
the rarer. For if this medium be rarer within
the sun’s body, than at its surface ; and rarer
there, than at the hundredth part of an inch
from its body ; and rarer there, than at the
orbit of Saturn ; I see no reason why the in*
crease of density should stop any where, and
not rather be continued at all distances from
the sun to Saturn, and beyond. And though
this increase of density may, at great distances,
be exceeding slow, yet if the elastic force of this
medium be exceeding great, it may suffice to
impel bodies from the denser parts of the medium
towards the rarer, with all that power
which we call gravity.”
I shall make an extract also from Mr.
Coffc’s Preface to the Translation of Sir I.
236 GRAVITY AND LEVITY
NEWTON’S Work, in order to convey to the
Superficial reader, an idea of the doctrine of
gravitation :
” that we may begin our reasoning
from what is most simple and clearest to us,
let us consider what is the nature of gravity
on earth, that we may consider it in the
heavenly bodies, situated at a vast distance.
It is now agreed, by all philosophers, that all
circumterrestrial bodies gravitate towards the
earth ! ! ! That no bodies really light are to be
found ; that what is relative levity, is not
true levity, but apparent only; and arises
from the preponderating gravity of the contiguous
bodiesv Moreover, all bodies, gravitate
towards the earth ; so does the earth again,
towards those bodies. That the action of gravity
is mutual, and equal on both bodies, is
thus proved, Let the mass of the earth be distinguished
into any two parts whatever, either
equal, or any how unequal : now if the weights
of the parts towards each other, were not mutually
equal, the lesser weight would give way
to the greater, and the two parts joined together,
would move, ad infinitum,in a right line towards
that part to which the greater weight tends :
which is altogether against experience. Therefore,
we must say, that the weights of the parts
are constituted in equilibrio; that is, that the action
ofgravity is mutual and equal on both sides.
The weights of bodies, at equal distances from
OF SOLIDS AND LIQUIDS. 237
the centre of the earth, are as the quantities of
matter in the bodies : this is collected from the
equal acceleration of all bodies, that fall from
a state of rest, by the force of their weights ;
for the forces, by which unequal bodies are
equally accelerated, must be proportional to the
quantities of matter to be moved. Now that
all bodies are in falling equally accelerated, appears
from hence, that when the resistance of
the air is taken away, as it is under an exhausted
receiver, bodies falling describe equal
spaces, in equal times.”
The equal distances which bodies describe
in equal times, whose densities are altogether
unequal, evidently prove, that weight and motion
are different from each other ; and that the
acceleration of motion, in falling bodies, depends
more on the nature of the medium in
which they are placed, than on the abstract
quantity of matter which they contain ; hence
it is, that a feather and a guinea, a rare and a
dense body, placed in an exhausted receiver,
are found to fall from equal heights, in equal
times. The weight of a body, and the motion
of a body, do not, therefore, altogether depend
on the quantity of matter in each ; we may
consequently infer, that this accelerated motion
which dense bodies acquire, in their passage
from great heights, through rare media, depends
more on the difference which exists between
238 GRAVITY AND LEVITY
them, and the rarified medium through which
they pass, than from any attracting power iu
the earth : if they fall in water, their motion is
retarded when they reach the solid matter of
the earth, it is altogether arrested ; they are
resisted by it more than they press it ; their
weight is actually, and absolutely, annihilated.
But if these effects arise from the relation which
exists between the quality of the medium, and
the matter by which they are surrounded, they
cannot arise from the attracting power of the
earth ; and, if they do not arise from the atr
tracting power of the earth, it must necessarily
follow, that gravity gravitation, or weight, is
a relative, and not a positive term. The
question then is, By what standard is this
relation to be measured? I answer, the
density which the same bulk of matter contains,
with relation to the rarity, of the
same bulk of matter which it displaces : it
is the density, or tenuity, of the medium, which
is displaced, with relation to the density, or
tenuity, of the body which displaces it, which
determines whether a body shall descend, or
ascend, or remain suspended ; and constitutes
the standard of measure. Gravitation, therefore,
properly defined, is the pressure downwards
which dense bodies produce, on such as
are rare; and levity is the pressure upwards
which rare bodies produce on such as ars
OF SOLIDS AND LIQUIDS. 239
dense ; or in other words, the rise or fall of
bodies in different moveable media, whether
solid, liquid, or gaseous, altogether depends on
the quantity of matter which those bodies severally
contain, with relation to the quantities of
matter which they displace.
It is owing to this relation which exists between
the subject which fills, and the matter
of the medium which has been dispossessed ;
that bodies of unequal bulks, have unequal
weights, in the same medium ; and, on the contrary,
that bodies of the same bulks, have un^
equal weights, in media of different densities ;
the increment of weight will be in proportion
to the decrement in the density of the medium;
and in proportion to the increment in the den*-
sity of the medium, an increment in the levity
of the body will ensue. The facts which
prove the truths of these propositions are so
universal and common, that it may, perhaps,
be considered superfluous in me to detail
them. There is not a brave sailor, who assists
at the capstern, in heaving up an anchor
from the bottom of the sea,.but knows, that the
force, or purchase, which is necessary to raise
the anchor from the surface of the sea to the
bows of the ship, is much greater than it is from
the bottom of the sea to the surface of it; the hir
crease of weight, or pressure downwards,
which the anchor has acquired in the air, above
240 GRAVITY AND LEVITY
what it contained in the water, is exactly equaF
to the difference which exists between the density
of the-water, with relation to the rarity of
the air ; the quantity of which may be ascertained
by means of a pair of scales, suspended
by a beam, with \<teights which are placed in
one of the scales, as the standard of that difference.
It is owing to the same cause, that
a cork is heavy in air, and light in water ;
and that iron is heavy in water, but light in
quicksilver ; that a bullet of lead, and a bullet
of feathers, of equal bulk, fired, at the same time,
from the mouth of the same cannon, take very
different directions. The feathers float in the
air, and are often balanced in it, but the lead,
on the contrary, after the impelling force is lost,
which it had received from the expansion
of the air, which the gunpowder contained,
gradually sinks to the surface of the earth ;*
and, as the pressure downwards is the natural
measure, or test, which exists between the different
degrees ofdensity, and of rarity, which different
bodies within the same bulk possess ; so the
* That a body loses as much of its own weight, as the
weight of the body which it displaces, is a fact which was
known as far back as the time of Archimedes : although the
story is a common one, it nevertheless, is very decisive.
Hiero, king of Syracuse, suspecting that a crown which he had
ordered a goldsmith to make fur him of pure gold, contained
OF SOLIDS AND LIOUID&. 241
pressure upwards, or levity, is the natural test
of the rarity of their composition, with relation
to the density of the medium which they have
displaced. Matter is not dense, because it is
heavy ; nor rare, because it is light ;
it is not
expansible, because it is motive; nor motive, because
it excites illumination. Those who form
these notions, have viewed the subject in an
improper manner ; they ascribe to effects the
power of cause they mistake the shadow for
the substance the secondary and accidental
property of matter, for that which is primary
and essential.
It ought, on the contrary, to be stated, that
matter is heavy, because it is dense ; that it is
a quantity of base metal, or alloy, ordered Archimedes, to
verify the fact, without mutilating the crown. After much
deliberation on the subject, it occurred to him, at the time
he was in a bath, that his body was much lighter in water,
than it was in air ; and that the cause of this difference, must
arise from the difference between the density of the medium of
water, and of air; he, therefore, ordered a crown of pure
gold to be made, which balanced the other in the air : but
upon weighing them both together in water, he found that
the first was much lighter than the second; consequently,
that that difference must have arisen from its containing matter
in it, less dense than gold. It is added, that Archimedes
was so enraptured with the discovery which he had made,
that he forgot that he was naked at the time ; and had the
indecency to run through the city in that condition, crying out,
I have found it, I have found it ! ! !
R
GRAVITY AND LEV1T\
light, because it is rare ; and that it excites
flavor and odor in sentient beings, because it is
motive. Gravity and levity, therefore are terms
which are employed to express the relative
degrees of difference which exist in the quantities
of matter, contained by different bodies,
within the same magnitudes ; and as the levity,
or the gravity the rising, or the falling, which
is in consequence produced, is entirely limited
and confined to the medium alone; I
contend, that to ascribe those effects to other
causes, and more especially to the energy of
powers, residing in bodies, which are situated
at distances, the most remote from each other
that can be conceived acting where they are
not is not only a violation of every principle
of legitimate inquiry, but of the first rules of
philosophising, adopted and recommended by
the illustrious NEWTON himself; namely, that
no more causes ofnatural things are to be admitted,
than are both true and sufficient to explain
the phenomena. In order, however, that those
phenomena should be explained, from those
principles, it becomes absolutelynecessary, that
the order of nature should be inverted, and destroyed
; instead of the matter of which this
world is constituted, proceeding, as it does,
from the most dense, to the most rare ; it ought
to proceed from the most rare, to the most
dense; the solid base ought to occupy the
OF SOLIDS AND I IQUIDS. 243
medium which is filled by the whole of the atmosphere,
and the atmosphere ought to form
the nucleus of the earth itself.
As bodies of equal bulk, lose as much of
their weight, as is equal to the bulk of the
matter which they have displaced; it is very
apparent, that bodies of unequal densities, and
of the same bulks, will not be equiponderant
in one aiid the same medium. That when the
medium is rarer than the bodies which are
placed in it, the denser bodies will weigh
more than the rarer ones ; and, on the contrary,
when they are placed in media of greater rarity
than themselves, the body of the greatest magnitude
will acquire a greater quantity of weight
than the smaller one ; thus it is that different
masses of copper, and of gold, which were balanced
in water, will be found to weigh very
unequally in air ; and if a piece of cork, and a
piece of lead, were balanced in water, it will
be found that the cork will acquire a greater
increase of weight than the lead ; and that the
weight of both will increase in proportion as
the density of the medium decreases; consequently,
that all bodies are lighter nearer the
surface of the earth, and heavier in the uppermost
part of the firmament. It is, therefore,
not only not true, that all bodies are mutually
heavy, but I contend, that instead of the gravity,
or the weight, of bodies increasing, in pro-
R2
244 GRAVITY AND LEVITY
portion as the squares of the distances from the
earth decrease ; every fact of which we have
any knowledge, falsifies the assertion, and
establishes, in a manner the most decisive, the
truth of the contrary proposition; namely, that
the gravitation, or weight of bodies, increases
in proportion as the squares of the distances
from the earth increase.
It is owing to this increase of density which
water acquires, in relation to the rarity of the air
in the upper regions, that we behold it descend
from the medium above, to the plane surface,
in the form of rain, of snow, and of hail ;
that water confined in a bucket, suspended
in the air, presses not only upon the bottom,
but upon the sides also of the bucket,
in proportion to the quantity of water in it.
The same effects take place upon the floodgates,
by which water in docks and canals
is confined, when the pressure of the water
within, is only resisted by the medium of air
without: and it is a well known fact, which I
have myself ascertained, that if a bottle full of
air, closely corked up, is sunk into the sea by
means of a heavy weight attached to it, that
the pressure of the water will overcome not
only the resistance of the air in the bottle, but
of the cork also, and force it into the bottle. I
have no doubt, that if the cork had wires passed
OF SOLIDS AND LIQUIDS. ‘ 245
through it, and the bottle were sunk to a
great depth, that the unresisting nature of the
air, with relation to the pressure of the water,
would break the bottle as perfectly as if it were
placed under a mass of granite : and there is
no proof, more obvious of the weight of water
upon air, than the condensation which air undergoes
when it is confined in a bladder, and
sunk in water.
These different facts, and a multitude of
others, which I might adduce, altogether prove
the density of water, with relation to the rarity
of the air; the pressure ofweight in the one, with
respect to the unresisting nature of the other.
A bucket full of water in water, suffers no
weight, (provided the wood is of a medium density
with the water 😉 neither does the floodgate
sustain any pressure, when the water on
the outside is at the same level as it is on the
inside. If an ocean of quicksilver were to be
placed on the outside of the flood-gate, it would
overcome the resistance of the water within it,
and the same effects would take place by the
action of the quicksilver on th gate, as took
place by the action of the water on the bottom
and sides of the bucket, while it was suspended
in the air. Cases such as these tend to showthat
the pressure which is produced by fluids, altogether
depends on the diminished resistance
246 GRAVITY AND LEVITY
which is opposed to them, by the surrounding
medium. The same effects take place when
fluids of different degrees of density, are mixed
and diffused together ; the denser fluid will
sink ; the rarer will rise. Although fluids, with
relation to each other, subsist in a state of
equilibrium, they, nevertheless, have weight,
when they are placed in media of greater rarity
than themselves ; the question is riot, whether a
bucket of water has weight in air, but whether
any solid substance, when placed at the bottom
of it, would be more pressed upon, than it
would be, if it were placed near the upper surface.
The experiment wjiich proves the question,
is decisive in itself.
If a glass tube, of an inch in diameter, is filled
with water, and a piston immersed in it, which
is suspended from the arm of a balance ; the
same weight, in the opposite scale, will balance
the piston, in whatever part of the column of
the fluid the piston is immersed ; and if the
same piston, balanced in the same way, be immersed
in any part of a volume of water of any
breadth, or depth, however great these may be,
the additional quantity of water in which the
piston is immersed, will not add one particle
to its weight ; the measure of one ounce,
which kept the piston suspended in the
tube, of oue inch bore, at the depth of one
foot, will not have that weight increased,
OF SOLIDS AND LIQUIDS. 247
if the piston were immersed in the wide ocean
itself.*
* It is owing to the relative weight which particular bodies
possess, with relation to the medium by which they are surrounded,
that advantage is taken of this property, and that
it is made instrumental to the most useful purposes. Jt is
owing to the tendency downwards, which lead, or iron,
possesses, with relation to atmospheric air, that it becomes a
power mechanical ; a power which is able to set in motion a
number of wheels, so equally and admirably adapted to the
nature of the power which causes them to move, as to produce
a regular and uniform motion on a dial, or plate, so divided
into parts, that a precise knowledge of time may be ascertained
by the different spaces over which the index is made to
move. The effects thus produced the motion which the
index describes however regulated it may be by the mechanical
construction of the machine, is altogether to be referred
to the gravity, or weight of the lead, as the prime mover of the
whole ; the weight altogether depending on the density of the
lead, with respect to the rarity of the atmospheric medium in
which it is placed. In order, therefore, that this power should
be always the same, an absolute necessity exists, that a sameness
between both should subsist. If the atmospheric medium,
instead of being the same, should occasionally vary,
the relative gravity of the weights will be, consequently, altered,
if the medium be rarer, the weight will be heavier,
and the clock will, consequently, be made to move faster ;
and if the atmosphere be more dense, the relative gravity of
the lead will be less, and the pull, or drag, on the different
wheels will, of course, be diminished ; and by being diminished,
the motion of the index will require a longer period
in performing its revolution ; it would move slower, if the
weight were immersed in water, tban in air ; and in atmospheric
air, than if suspended in an exhausted receiver.
CHAPTER Xtt.
GRAVITY AND LEVITY OF GASES,
THE observations which I have made on the
state of equilibrium, and of weight of liquids,
equally apply with respect to the equilibrium
and the weight of gases also. If any given
quantity of gas of the same quality as that of
the surrounding medium, is received in a close
vessel, it will be found to subsist in a state
of equilibrium, or of balance. When the receiver
of an air-pump is placed over the balance,
having the bottle of air suspended from
the beam on one side, and which is counterbalanced
by a weight on the opposite scale ; if
the air is exhausted, as far as it is possible, out
of the receiver, the air confined in the bottle,
will be found gradually to preponderate, and to
be heavy. The weight which the air in the
bottle has acquired, or, more properly speaking,
the weight which has been generated, is
GRAVITY AND LEVITY OF GASES. 249
exactly equal to the loss of resistance, which
the medium of air in the receiver has sustained,
in consequence of the rarefaction which it has
undergone. By artificial means such as these,
the precise degree of difference which exists,
between the density and rarity of different
gases, may be ascertained ; the number of metallic
grains employed, are standards t)f measure,
which are necessary to restore the counterpoise,
in the opposite scale, and constitute
the measure of the difference which exists between
the density of the air in the bottle, and
the rarity of the air external to it
; it gives
the relative, but not the absolute weight. If
a perfect exhaustion could be effected, we
should, in that case, have the absolute, not the
relative weight: but as this event cannot be
accomplished, we have, in every case, the relative
weight, and not the absolute one.
Various experiments have been made to ascertain
the relative weight of different gases,
not only with respect to each other, but with
respect to the utmost state of rarefaction that
can be attained : it has been found, that a
pint of atmospheric air, inclosed in a bottle, requires
the measure of about? metallic grains, to
restore the equilibrium, that hydrogen gas is
the most rare, because the lightest and carbonic
acid gas the most dense, because the
260 GRAVITY AND LEVITY OK GASES.
most heavy. The comparative degree of density,
and of rarity, between each, may be ascertained
in a different way ; it may be ascertained
by exhausting the air in the bottle, while the medium
of atmospheric air, or of any other gas, is
allowed to remain, external to it ; instead of the
rarefied air which is left in the bottle, being
balanced as before, it is found that it presses upwards,
and is lighter ; and the number of metallic
grains which are necessary to be added to
it, in order that the equilibrium may be restored
is the proper measure of the difference
which exists, between the rarefied air in the
bottle, and the dense air which has been displaced
by it.*
By means, such as these, we infer, that the
quantities of matter contained in different bodies,
are in the compound ratios of their magnitude
and densities ; and that the different mea-
* It ought, however, to be observed, that in measuring
the relative density and rarity of different bodies, by any
given standard that may be employed ; whether such standard
be solid, liquid, or gaseous, that no precise accuracy can be
expected, unless the standard which is employed is of the
same bulk, as the bulk of the matter which is to be measured
; for as every dense body loses as much of its weight,
as is equal to the bulk of matter which it displaces, the standard
of the greatest bulk, will necessarily be lighter than the
one of less bulk, and vice versa.
GRAVITY AND LEVITY OF OASES. 251
s.ures which we employ, give us the relative, but
not the absolute weight; they prove that different
gases, when they are of different densities,
press as much as they are pressed, and resist
as much as they are resisted ; that they are
neither heavy nor light, but subsist in a state
of equilibrium, or of balance; that, on the contrary,
when they are of different degrees of
density, or of rarity, they are either heavy or
light, according to the. quality of the medium in
which they are situated.*
* Sucb is the expansive force which the air exerts, when
external resistance is diminished and removed, that in making
experiments to ascertain the degree of density, which any
given quantity of it possesses, with relation to the rarity of
the medium of air by which it is surrounded or the rarity of
the one, with relation to the density of the other ; that it is
necessary to inclose it in vessels of copper, or some other
metallic substance ; as bottles made of glass, unless they are
very strong, are found generally to crack, and break. It is
more especially the case, when a large volume of air is condensed
into a smaller volume, the condensation which is
produced, must not be considered the cause of Us expansibility
; it only proves, that the expansibility of air may be
pvercome, by an external force : but it does not prove, that
pressure is able to generate expansibility in bodies, which are
not expansible. Pressure can no more create, or impart,
expansibility to air, than it does to lead, or to water ; air is
expansible ab initio, and which pressure can neither create,
nor destroy.
252 GRAVITY AND LEVITY OF GASES.
It has been in subservience to the false
proposition, so pertinaciously maintained as
true, that all bodies are mutually heavy, or
gravitate towards each other, that philosophers
have been led to confound the attributes
of those bodies, which possess a repulsive
power, with those that neither attract
nor repel ; but which merely act by the relative
degrees of density, and of rarity, which
they severally possess. As density, however
subtile it may be, is inseparable from
the existence of materiality ; all bodies under
different circumstances, may, unquestionably,
be said to possess, with relation
to each other, levity or gravity. In estimating,
however, the attributes of different bodies
with each other, that estimate ought ever
to be derived from the attributes which are
primary and essential, and not from those
which are secondary and accidental. There
are a variety of bodies which possess the
relative and accidental property of gravity, and
of levity, and which do not act by virtue of the
one, or of the other. A muscle, for example,
may be said to have weight in air, and levity
in water ; and yet it is not from its gravity
or levity, that its power is derived. A
spring may be said to have weight, and yet
it will not be pretended, that it is to its
GRAVITY AND LEVITY OF GASES.
weight, that the pressure it produces is to be
referred.
Whoever reflects on the forced and unnatural
means which it is necessary to employ, in order
to ascertain the rarity, or the density the
levity or gravity of air, will be led to conclude,
that it is not by these attributes that its power
ought ever to be meted, or measured ; for although
its expansibility is not only equal to, but
greater than its weight its weight is not equal
to, but much less than its expansible power. As
well might the muscular power of the most
gigantic arm, be legitimately estimated, when
it is paralysed by the pressure of a weight, or
when it is rendered motionless, by being rivetted
and fixed to a post, by the strongest chains,
as to ascribe to the weight of air the power it
possesses. Whenever air is confined in close
vessels, whose solid sides have the power to
restrain its expansive force ; it may then be
said to subsist, in a state of capacity, without
power ; of density, and of rarity, without expansibility
; it has then as great a tendency to
fall, as it has to rise, and is rendered altogether
subservient to the laws of the vessel in which it
is inclosed : in cases such as these, it is internal
force overcome by external resistance. When
ever external resistance is diminished, or removed
; whenever air is released from this
GRAVITY AND LEVITY OF GASES.
forced and unnatural situation, and is restored
to space free and unconfined, its power is
displayed by its activity : it neither acts by
virtue of its density, or rarity, of its gravity or
levity; it does not, like incompressible bodies,
confine itself within the same limited bounds,
nor press upwards or downwards only, from its
levity or gravity ; but expands to an indefinite
extent, from a centre to the whole circumference,
equally in every direction. The pressure
which is produced on the surrounding
medium, by the expansible power ofgases, is as
different from the pressure which is produced
by liquids, as it is from the pressure produced
by solids.
While the pressure downwards of a liquid,
placed in a medium rarer than itself, is limited
and confined to the perpendicular height only ;
the pressure produced by the weight of solid
bodies, on the contrary, congregates, as it were,
from the whole circumference, to one point, at
the bottom. The surface of a plank, an inch
in diameter, will suffer as much pressure from
a column of water, of an inch in diameter, and
of the height of twenty feet, as it will do from
a column of water of the same height, whose
diameter is as v/ide as the ocean itself. The
pressure, on the contrary, of solids, comprehends
the aggregate quantity of matter conGRAVITY
AND LEVITY OF GASES. 255
tained by the whole mass, at the centre of gravity
at the bottom, as it is called : (a centre at
the bottom!!!)*
The error of confounding the attributes of
gases with those of liquids, and of liquids with
those of solids* is not more striking than the
fashion which prevails, of confounding pressure
with resistance, power with capacity the capacity
which some bodies possess, of receiving
power through the medium of participation
from other bodies, with those which possess it
* The centre of gravity is supposed to be that point in any
body, about which all its parts are equally balanced, or kept
in equilibrio. In regular and homogeneous solids, this point
is situated at equal distances from the extremities. In irregular
bodies, however, which possess unequal degrees of density,
this point, or centre, as it is called, instead of being
situated in the middle of the line, is often more on one side
than the other ; the point of suspension altogether depending
on the equality of the matter which subsists on one side, with
respect to the other. ” 1. The pressure of fluids is in proportion
to the base, and perpendicular height of the fluid, whatever
be its form or quantity. 2. The pressure upon the
bottom of a conical vessel, is equal to the pressure upon the
bottom of a cylindrical one, of the same base and height.
- The pressure of a fluid upon any indefinitely small part of
the sides of the vessel which contains it, is equal to the weight
of a column of the same fluid, whose base is the part pressed,
and whose height is the distance of that part from the surface
of the fluid.” Enfuld.
256 GRAVITY AND LEVITY OF GASES.
essentially and inherently. I shall, therefore,,
proceed in the ensuing chapter, to mark the
distinction which exists between them, as being
absolutely necessary to understand the various
phenomena of nature which take place, and
more especially to show that gases do not act by
gravity or levity.
CHAPTER XIII.
EXPANSIBILITY DIFFERENT FROM IMMOBILITY,
AND MOBILITY, FROM FLEXIBILITY AND
ELASTICITY.
So totally and absolutely inert is the solid
matter of which the world is composed, that it
possesses, within itself, no power by which it
can act; neither the mass altogether, more than
the smallest particle of sand, would ever alter in
form or in position, unless it were acted upon
by agents external to itself. It is in consequence
of this natural tendency in solid matter
to remain permanently the same, offering resistance
alone to the action of those bodies by
which it may be assailed ; that it is said, to be
imbecil and inert, and to which, the term immobility
ought especially to be applied.
Whenever solid matter is acted upon, and
the resistance which it opposes is overcome ;
the changes which it is made to undergo perpetually
wear away : it gradually verges from
258 IMMOBILITY, MOBILITY, ETC.
the state of activity into which it had been
excited, into the passive and quiescent state
which is natural to it. This is the end
which invariably takes place, when one mass of
solid matter is made to act upon another; the
first loses as much of its own motion as it imparts
to the second, insomuch that the quantity
of change which is excited in the one,
entirely depends on the quantity of power communicated
from the other. This capacity to
be acted upon, this indifference to motion or
rest, is called mobility ; and the change which
the body undergoes during the transition from
one place to another, is called motion.*
The effect or change which is produced by a
moving power on a solid substance, altogether
depends on the nature of its construction. If
it cracks or breaks without yielding, it is said
to be brittle, such as glass or flint. When a
body yields without cracking, it is considered
asflexible ; this is the case with lead, with iron,
and with a variety of other bodies. This capacity
to be bent by the agency of external powers,
which particular bodies contain, without
* It is surprising Mr. Locke should have misapplied, as he
has done, the term mobility, and confounded capacity and
power together. Mobility he calls a power to be moved, instead
of a capacity or aptitude to be moved. In like manner
Sir Isaac Newton calls it a vis inertia.
FLEXIBILITY AND ELASTICITY. 259
possessing any inherent power of unbending
themselves, is therefore called flexibility ; or as
Dr. JOHNSON expresses it,
” the quality of
admitting to be bent.” The nature of this
capacity to be acted upon, is exemplified in a
common piece of iron or of wood. The particles
of matter, of which these substances are
composed, are unable to resist the power which
acts upon them. The inferior strata become
contracted, the upper lengthened, both are distorted
and bent; and finally, if the external force
be increased beyond a certain point, the bond
of continuity between* the individual particles
becomes separated, and the iron or wood snaps
or breaks. The whole effect which has been
thus produced, is evidently to be referred, not
to a power resident in these bodies, but to the
agency of the external force impressed upon
them ; it was resistance overcome by an overcoming
force.
This capacity of admitting to be bent and to
be moved by an external force, which flexible
bodies possess, extends to other bodies which
have the power of restoring themselves to their
former situation, after the external force is
removed, through the agency of which they
had been made flexible : bodies such as these,
are called elastic; of this description are steel,
whalebone, catgut, &c. &c. The distinction,
therefore, which exists between elasticity and
s 2
260 FLEXIBILITY AND ELASTICITY.
flexibility consists in this ; elasticity has the
capacity to be bent, and the power to restore
itself to its natural and original situation from
whence it had been forcibly distorted and withheld
; while flexibility, on the contrary, has the
capacity to be bent only, without the power of
unbending itself. Dr. JOHNSON, therefore, with
that wonderful power of discrimination which
on every occasion he is found to possess ; very
properly defines elasticity, to consist of a ” force
in bodies by which they endeavour to restore
themselves to the position from whence they
were displaced by an external force.” By the
substraction of which, such is the peculiarity
in the arrangement of which the elastic substance
is composed, that it has the power of
returning back to the position it was in before,
in which condition it remains.
That the return to its original situation only
of the elastic body, by the snbstraction of the
external force; is the true meaning and application
of the wrord elasticity, is further proved by
Sir ISAAC NEWTON. In his book on optics, he
says,
” when a body is compact, and bends or
yields inward to pressure, without any sliding of
its parts, it is hard and elastic, returning to its
figure with a force arising from the united attraction
of its parts.” If we, therefore, examine
the definition of the word elasticity as
{riven- by Johnson, and illustrated by Newton,
FLEXIBILITY AND ELASTICITY. 261
and as it is generally used at this day, we must
conclude that it is not only retained within the
narrow limits to which the fibres are confined,
but that it is never exerted without the intervention
of an external power impressed upon it.
Elasticity consequently consists of two properties
; of weakness and of power, of passion
and of action, of suffering to be, and of becoming
to be, offlexibility through the agency of an
external force, and secondly, ofre-action from
internal and inherent construction ; as when
Shakspeare says,
” when splitting winds make
flexible the knees of knotted oaks ;” the splitting
winds constitute the external cause, by
which the flexible knees of knotted oaks were
made to bend. Such, however, is the internal
construction of the fibres of which the oak is
composed, that they are able to return back to
their original state, as soon as the splitting
winds have ceased to rage. It is this dead
capacity of being acted upon, and of being
changed without the power of resisting action,
of being moved without the power of moving
itself, of being modelled without the power of
modellingitself, which constitutes the mobility
of LOCKE, the vis inertia of NEWTON, the flexibility
and elasticity of our modern philosophers.*
* This capacity to be acted upon is proved in a manner the
most decisive, by the commutation total and complete which
262 EXPANSIBILITY.
If I proceed from flexible and elastic bodies,
to consider the attributes of those which are
essentially expansible, although they possess, in
common with the former, the capacity to be
bent into different forms, aqd even to be compressed
from a larger to a smaller volume, by
the agency of an external force ; they nevertheless,
differ from both in points the most essential.
Instead of requiring the agency of external
pressure, in order that they may be enabled
to unbend and expand, external pressure alone
is the means by which this expansive power is
bounded and confined; instead of being like
flexible and elastic bodies, naturally passive
and artificially active, they are naturally active
and artificially inert ; they are made flexible by
pressure, but are expansible without it. The
instant external pressure is removed, this exfood
undergoes, not only with respect to quantity but to quality
also, not only with respect to configuration in general, but
to essential properties in particular, by the digestive and assisimilating
organs, with which animals and vegetables are endowed.
Having detailed at considerable length the nature
and relation which subsist between capacity and power in my
system of physiology ; to that work, I must refer the reader,
if he be desirous to understand the nature arid power of life
in converting the capacity of matter from a dead to a living
state, from a state of dispersion to a state of combination,
from a multitude of parts into one organised system, endowed
with animation and action.
EXPANSIBILITY. 263
pansive power is immediately developed from
its confinement and displayed by its activity ;
spreading and dilating to the utmost limits
which the imagination can conceive; it communicates
motion to the mobility of different bodies,
and causes pressure on all.
It is this original and essential power which
abiding in gaseous and aeriform bodies, gives
them the generic character of expansibility,
strictly so called; which identifies their nature
and distinguishes them from those belonging to
every other class. The difference between
them appears to me as great as they are important
; and will be rendered apparent, if compared
together. The motion or force which is
manifested by steel and other bodies considered
as elastic, is altogether produced by the unnatural
direction given to the particles of matter
of which they are composed ; the expansibility
of gaseous bodies proceeds from the spontaneous
and natural tendency of expanding, inherent
in them. In the one, the direction of the motion
produced, always corresponds to the particular
direction of the particles of matter of
which the elastic substance is constituted. In
the other, the dilatation which takes place, extends
equally in every direction. In the former,
the degree of motion produced is confined
within the narrowest limits ; in the latter, the
expansion is indefinite in its extent; while the
264 EXPANSIBILITY.
addition of an external force is absolutely necessary
to make a flexible body to become an
elastic one ; it is by the substraction of an external
force that gaseous bodies are enabled to
expand. Elasticity, therefore, is merely m
effecto, a power which is derived, but which
does not exist essentially ; it is an excited, not
an inherent power, whose energy immediately
ceases as soon as the compressing cause is removed,
and the particles of which the elastic
body is composed have returned to their natural
and original situation.
In matter, however, which is essentially
expansible, it is far otherwise ; instead of m
effecto, it is causa motus ; not derived from
without, but which subsists inherently within ;
not produced by external means; it is through
the resistance alone, opposed, by external
means, that this expansive power can be suspended
or suppressed. The difference may be
proved by simply placing a flexible, an elastic,
and an expansible body together, under the
same relative situations. If a small portion of
air enclosed in a large bladder is placed under
the receiver of an air-pump, with a piece of lead
or steel, the change which the air undergoes is
totally different from that of the other two.
In proportion as the air within the receiver
external to these bodies is abstracted by exhaustion
; it is found that neither the steel nor
EXPANSIBILITY. 265
lead undergo any change whatever; on the
contrary, the air within the bladder dilates and
expands to its utmost extent.
What is the extent to which air may expand,
with what velocity it may move, and what
resistance it is able to overcome, must necessarily
be very difficult to ascertain. Mr BOYLE
was of opinion, that air was capable of expanding
in the proportion from 1 to 1000 times. Sir
ISAAC NEWTON considered this property of air
to be almost unlimited and unbounded ; that it
extended, perhaps, to one million times more
than its original bulk ; that is to say, that one
cubic foot of air, at its initial state, was capable
of dilating and filling the whole space of one
million cubic feet in extent. Dr. GREGORY, in
his astronomy, mentions an opinion, which he
probably derived from Newton ; that if a cubic
foot of air were removed to the elevation of one
semi-diameter above the surface of the earth,
that it would expand and extend as far as the
orb of the planet Saturn. It is not my present
intention to examine the accuracy of these opinions,
or attempt to reconcile the difference
which exists between them. However discordant
they may appear in point of quantity, they
agree in matter of fact, and tend to establish the
wonderful power of expanding which air essentially
contains.
The late ingenious Mr. SMEATON has pub266
EXPANSIBILITY.
lished a table in vol. 51, of the Phil. Trans.:
with the intention of shewing the velocity with
which air has the power of moving, and which
is known under the appellation of wind* This
table is founded on a great number of observations
made by himself in the course of his practice
in erecting windmills.
Miles per Hour. Feet per Second of time. Names,
1
EXPANSIBILITY. 267
If we reflect for a moment on the energy
which a power such as this must exert, we
shall be at no loss to conceive the resistance
which it is capable to overcome, and the rapidity
with which bodies exposed to its force are
carried along. GARNERIN, the aeronaut, on
the 31st of June, 1802, ascended with another
gentleman from Ranelagh in a car, suspended
from an inflammable air balloon, and in fortyfive
minutes descended near the sea, four miles
frpm Colchester, a distance of sixty miles.
Allowing no time for the elevation and depressipn
of the balloon, but supposing the whole
medium of the atmosphere, and in which no wind consequently
exist. 2. Winds may be divided according to the periods or
times which they blow, and the direction in which they more.
- Monsoons, or periodical winds, are those which blow half
of the year from one direction, and the other half year from
the opposite one, and are generally found in the China and
Indian seas. 2. Trade winds, which resemble the monsoons,
and may be considered a species belonging to the same genus.
They are confined to the wide ocean only, at a considerable
distance from the shore, at about 28 on each side of the
equator, and are often interrupted by variations in the intensity
and direction of them, the equilibrium of the air being
often restored, and a cairn produced. At other times, light airs
taking place in different directions. 3. Variable winds> or
such as obey no regular rule, but which change in their directions
at different times, without any known or assignable
*:attse, as we behold in these latitudes.”
268 EXPANSIBILITY.
period, occupied in transferring it, in a path
nearly parallel to the earth’s surface ; its velocity
must have been at the rate of 80 miles per
hour, or 1 17 feet per second of time. If a mass
such as this could have been hurried along
with such a velocity, how much faster may we
not suppose, those vast collected masses of
vapors, known by the name of clouds, can
be made to move? How much more intensely
fast must air itself move by itself, without
impediment or obstruction? When we reflect
on the energy which such a power is
capable of exerting, we can be at no loss to
conceive how it is that the air which is generated
during the process of putrefaction and fermentation,
has the power to separate and to
decompose vegetable and animal bodies altogether
into parts, and tin ally to resolve those
parts from a dead to a common state, to eject
corks from bottles, to fissure and break into
pieces the bottles themselves in which effervescing
liquors are contained, to overcome the
bond of union by which bodies the most solid
and compact are held together, to dislocate
and devallate mountains of the greatest magnitude
into rocks, to lacerate those rocks into
fragments, to pulverise and granulate those
fragments into sand, the most subtle and minute,
we can be at no loss to understand
how it is that the small quantity of air which is
EXPANSIBILITY. 269
generated and extricated from gunpowder during
the process of detonation, is enabled to sap
and to undermine the strongest fortifications;
to project out of the mouth of a cannon a ball
to the immense distance of two or three miles ;
to explode the strongest shell from a mortar ;
to burst it into pieces, and carry death and destruction
to surrounding objects.*
In the various and multiplied discussions on
this subject, which I have had with numbers
of scientific men, and more especially with
many of my particular friends, who fill the
teacher’s chair in some of our most celebrated
schools of science in this metropolis, I have
not found an individual among the whole mass,
* Col. WILLIAMS, while serving at Quebec, filled different
iron bomb-shells of different sizes with water, and plugged
the fuEfhole close up, sometimes driving iron plugs with
a sledge hammer. When the water had been frozen, although
the plugs often weighed three pounds, they were
always forced away, by the sudden expansion of the air in the
act of freezing, like a ball impelled by gunpowder, to the
distance of 4 and 500 feet; and when the plugs were screwed
in the shell, the shell burst. Mr. Marian ascribes the expansion
that takes place at the point of freezing, not to the
extrication of air, because he says that water deprived of air,
expands equally ; he, therefore, refers the effect to the new
arrangement of the particles of the water which takes place,
in the change which they undergo from a fluid to a solid state;
it is very probable that both causes operate to produce the
effects.
270 EXPANSIBILITY.
who had any conception of expansibility subsisting
as an inherent and essential power, of
expansibility, independently of resistance. The
utmost extent of their knowledge was limited
to re-action alone ; to that sort of power which
is derived in consequence of external pressure.
It is, perhaps, still more astonishing’, that a
distinction so strong, and so well defined, has
not only been overlooked, but is, at this moment,
admitted by very few.
It appears to me very probable that the present
prejudices are merely the result of former
errors, handed down to us through the medium
of PROFESSOR GRAVESANDE and other commentators
on the laws of nature, as they have
been called, of Sir ISAAC NEWTON, who was
the original legatee. So far, however, from
considering these laws, to be laws of nature ;
from all the attention which I have given to
them, I am bound to declare that they are
mere assertions, contrary to nature ; mere abstract
terms, which require a condition of things
that in nature does not exist, but which, nevertheless,
is to be presupposed.
CHAPTER XIV.
ON THE RELATION WHICH EXISTS BETWEEN
THE EXPANSIBLE POWER OF GASEOUS BODIES,
AND THE RESISTANCE THEY ARE ABLE TO
OVERCOME.
IN the investigation of action in general, whether
original or derived, it is absolutely necessary
to ascertain the nature of the means rather
than of the end, of the cause more than of the
effect ; when the resistance is equal or greater
than the power of the body acting, the resisting
body continues passive and at rest ; when the
power is greater than the resistance, the body
moves ; the degree of motion produced, is the
proof or test which subsists, of the power in
the one, of overcoming the resistance of the
other;* so far, however, from action requiring
* Professor Gravesande ridicules the idea that action is possible
to exist without resistance : for who, says he, can conceive
the possibility of action without an obstacle ; soon after,
however, he allows resistance to be an impediment to action.
From these palpable contradictions the following corollary is
deduced, that the force and resistance are equal to one another.
272 FOWER AND RESISTANCE.
resistance, as is generally supposed, it is resisfance
alone that diminishes and ultimately destroys
action. Hence it is that bodies move
slower in a liquid than in a gaseous medium ;
faster through a liquid than through a solid one-
Notwithstanding this most obvious truth, it
is nevertheless contended by Sir Isaac Newton,
that the motion produced in different bodies,
is occasioned by a mutuality of power, subsisting
between them. It is far otherwise ; such
is the absolute inertness of the body which is
to be moved, that it is not only indebted to the
efficacy of the moving power for the velocity,
but for the line of motion also, which is produced.
The degree of motion which is produced
is the proof or test which subsists of the
power in the one, to overcome the resistance of
the other. It is by virtue of the inherent power
of acting, which animated beings in general
possess, that they are enabled to overcome resistance
and produce action, to act, without
being acted upon, to move without being moved;
that a horse is enabled to draw a cart
without the cart drawing the horse ; that the
pen with which I write is enabled to describe
the letters I am writing, the paper having the
capacity* alone of resisting the impulse which
*
By capacity I mean something which is passive only, and
by power something which is active and efficient. Capacity
POWER AND RESISTANCE, 273
it receives from my pen ; the degree of action
which is produced, does not so much arise from
magnitude, as from internal energy; from the
quantity of ponderable matter, as from activity
and skill. It is by means such as these, that
the strong in mind, but weak in body, are often
enabled to overcome the strong in body, but
weak in mind. It is in the skill which experience
is often capable of producing, that the
expert swordsman is enabled to overcome the
awkward rustic ; by which the little David was
able to slay the great Goliah,
It is this power which, in fact, constitutes
really and truly, not only vis motus, but vis
inertiae also; a power to move, as well as a
power to be quiet ; a power to act, and to resist,
as well as a power to yield, and to follow
impressions communicated and received.
It is by the expansive force of air, and of vapor,
that steam-engines are made capable of overcoming
the same degree of resistance, as the
supposed power of 10, 40, and 00 horses ; that
levers can balance, and raise, different weights ;
may be said to bear the same relation to power, as the obedience
of a servant to the will of his master as children to their
parents, as loyal subjects to the law&of the government under
which they live, and as the universe in general to the Deity
omnipotent, by whose infinite power it is governed and Coutrouled.
274 POWER AND RESISTANCE.
that whilst a ship in a calm is motionless bf
the pressure of the wind upon the sails, it is
enabled to overcome the resistance of the water,
It is owing to the resistance of the thing to
be moved, that is aseribable the impossibility
of finding out perpetual motion. The resistance
which is constantly exerted, by the friction
of the moving body, against the medium, or
sides of the matter in which it is placed, has an
unceasing and everlasting tendency, not only to
obstruct, and to weaken, but finally to destroy the
force of the moving power. Various machines,,
which are invented by the ingenuity of man, can
only diminish, they cannot annihilate resistance.
Whether the thing moved, is moved by the muscular
power of the hand by the momentum of
a rapid stream by the expansibility o’f air, or
the elasticity of fire, or any other mechanical
force whatever ; it ought to be considered as an
universal and undeniable truth, that the cause
of motion is separate and distinct, from the
thing moved, the one is the agent, the other
the patient ; the former is vis sine inertia, the
other inertia sine vi, a force without power, a
forceless force.
A vis inertiae such as this, is altogether sepa^
rate and different from the vis inertiae ascribed
by Sir ISAAC NEWTON, to matter in general,,
both dead and common ; the attribute to which
AND RESISTANCE. 275
he refers is mere capacity, not power ; it is by
calculating the different proportions which exist
between the power of the moving cause, and
the degree of resistance in the thing to be moved,
that is founded the whole science of mechanics.
So far; however, from supposing,
that in the motions which different bodies display,
there subsists between them a mutuality
of action, as Sir Isaac Newton asserts ; that
a stone draws a horse, as much as a horse
draws a cart; that a stone presses the finger,
as much as the finger presses the stone, [Quicquid
premit vel trahit alterum, tetntundem ab
eo premitur vel trahitur, si quis lapidem
digito premit, premitur et hujus digitus a
lapide* Si equus lapidem funi alligatum trahit,
retrahetur etiam et equus (ut ita dicam)
aequaliter in lapidem, &c. &c.] I contend, on
the contrary, that an assertion such as this is
erroneous in the extreme ; that it is thereby
ascribing equal powers to unequal causes ;
confounding together inanimate with animated
beings, as well as different kinds of matter,
whose nature and properties are altogether
different ; death and life, passion and action ;
things that are moved, with those that have
the power of moving; things which derive
power through the medium of participation by
an external force, with those which possess it
T 2
276 POWER AND RESISTANCE,
essentially, and in actuality ; and finally,, reaction
itself with resistance.
What analogy^ I would ask, is there between
the actions which flow from the powers,
that animated beings possess, and the passivity
of the common matter on which they
act between the reaction of a spring, and
the ponderable matter it is able to support ;
between the expansibility of air and of fire,
and the resisting bodies which they are able to
overcome and to project to the considerable
distances, which they are known to do?
So far from admitting the legitimacy of the
assumptions on which the third law of Sir
Isaac Newton’s system is founded, I contend,
that those assumptions are absolutely false;
I contend, that instead of reaction, being always
equal and contrary to action ; that it is
not equal, but that it is always less. I deny
altogether the third law, Lex, 3.
” Actioni contrariam
semper erit, et aequalem esse re-actionem
; sive corporum duorum actiones in se
mutuo, semper esse aequales et in partes contrarias
dirigi.”
It is apparent to me that, in propounding this
pretended law, Sir ISAAC NEWTON never had
in his contemplation the power which particular
bodies essentially possess, to produce
action. The very term re-action, which he
POWER AND RESISTANCE. 27?
employs, and the arrangement in which the
assertion is conveyed, show most clearly, that
he refers to the power possessed by elastic bodies
of reacting, and of returning from their
forced to their natural state. Had it been
otherwise, he would have inverted the order
and the arrangement in his terms ; instead of
saying, that reaction was equal to action, he
would have said that action was equal to reaction
; in either case, however, he would have
been incorrect He would have been incorrect,
because it is necessary in that case, to suppose
what is not, for the purpose of proving what is.
It is absolutely necessary to pre-suppose, not
only that the medium through which bodies act
upon one another, opposes no resistance whatever
to them, but that space should exist without
matter to fill it, and a vacuum be the natural
condition of the greatest part of space.
The illustrious author of this conjecture, it
appears to me, not only made it without proof,
but contrary to every principle in nature. A
condition of things such as that which has been
hypothetically supposed, I maintain is falsified
by every fact of which we are in possession ;
the plenitude of matter is the cause why a finite
power can never produce an infinite effect, and
why motion excited, perpetually diminishes,
and is ultimately lost ; it is the case with the
278 POWER AND RESISTANCE.
motion of a pendulum ; if a pendulum be set in
motion by an impelling force, the medium of
air through which it is made to move perpetually
opposes motion, without giving it : if reaction
were equal to action, the pendulum
would press the air, as much as the air presses
the pendulum, and motion perpetual might be
produced. Motion perpetual might be produced,
if we suppose that which is impossible,
that resistance could be taken away, not only
from the friction at the point of suspension, but
in the medium through which the arch is described
; if the reacting power of an elastic
body be 20, the resistance of the medium 5, the
body acted upon can only be 15. The action
produced in consequence of reaction, can,
therefore, neither be equal, nor greater; it
must, therefore, be less; if it were otherwise,
instead of the motion in a ball excited to
move, being forced ultimately to cease, it would
mofe for ever, and an infinite variety of effects
produced which these false assumptions presuppose.
On the truth or error which exists in the
assumptions, or principles, from whence different
sciences are derived, depend altogether the
truth, or error, of the conclusions which are
made. Instead of Sir I. NEWTON’S Laws of
Nature, as they have been called, being rules
POWER AND RESISTANCE. 279
of action, which all matter must obey, I contend,
that effects are constantly produced
throughout the system of nature, in violation of
them. I shall, therefore, proceed to examine
the various phenomena which different species
of matter display ; and, at the same time, show,
how much those phenomena are at variance
with the rules which those laws are intended to
describe.
CHAPTER XT.
OK THE INEQUALITY OF PRESSURE IN THE
AIR, IN CONSEQUENCE OF INEQUALITY OF
EXTERNAL RESISTANCE,
HOPING that the facts which I have advanced,
are sufficient and conclusive ; not only to prove
the expansive power of air, independently of
external influence ; and that the pressure which
it produces on surrounding bodies, is to be
referred to expansibility, not to density and
weight; I shall now proceed to detail the
effects which are produced by the air, when
there exists an inequality of resistance in the
medium by which it is surrounded.
Whenever the substraction of external resistance
takes place, from any one part, the
expansible force of the air becomes immediately
dilated, and directed to the particular
situation where the least resistance exists; a
change of pressure, consequently, takes place,
PRESSURE IN THE AIR, 281
from equality to inequality ; from radiation
equally every where, to projection unequally
somewhere. Is it not legitimate to conclude,
that it is owing to the unresisting state of the
upper regions of the firmament, that the whole
column of the atmosphere progressively decreases
in density, in consequence of increased
dilatation ; that while the expansion of the upr
per strata takes place, a, progressive diminution
of pressure from the top to the bottom,
throughout the whole atmospheric column, will
be the inevitable consequence, similar to a
small portion of air, enclosed in a large bladder,
under the exhausted receiver of an air pump ;
insomuch, that the pressure of the air, near the
surface of th^ earth, will be less in degree sideways,
and downwards, than it will be perpendicularly
upwards.
Instead of agreeing to the opinions which
now prevail, that the different strata of the
atmosphere increase in weight from top to
bottom, in a manner similar to a quantity of
fine carded wool, piled up and thrown into a
deep pit; the lower strata carrying the weight
of the upper, and being compressed by them ;
the actual condition of the atmosphere is the
very reverse of this ; the density which the
wool possesses, with relation to the rarity of the
medium in which it is situated, gives it weight ;
insomuch, that every particle of the wool
PRESSURE IN THE AIR,
to the weight of the mass, in a regular and progressive
degree, from the top, which weight becomes
concentrated at the bottom : so far, however,
from the lowerstrata of the atmosphere subsisting
in a state of condensation, like the lower
strata of the wool, from superincumbent compression,
the lower strata of the atmosphere
are in a comparative state of expansion, from a
diminution of superincumbent pressure. So
far from the lower strata of the atmosphere
supporting the upper, the upper strata are rather
pressed up by the expansive force of the
lower; instead of a progressive and gradual
sinking and condensing of the whole mass from
top to bottom, there is, on the contrary, a general
rising and lifting up of the whole mass,
from the bottom towards the top.
If the ascent of the atmosphere from the surface
of the earth, did not take place, how could
its existence, at the highest points of elevation,
be explained ? How could we account for that
immense mass, not only of water, but of different
bodies, which are there found mechanically
diffused, or chemically combined with it, in 3,
gasified state. The ascent of the air from the
surface below upwards, because less resistance
prevails, is not only a legitimate effect of the
physical properties which it possesses, but is
further confirmed by the propagation of sound;
the pulsations of the air against the auditory
AND EXTERNAL RESISTANCE. 283
iierves, are far stronger when they are directed
from the bottom to the top, than from the top to
the bottom; if it were not, therefore, for the
ascent of the atmosphere, the pulsations of the
air, would increase in force, in proportion as
they were conveyed downwards, through a
more expansible medium. Sound, from the
top to the bottom, is similar to what is experienced
by those who speak against the wind.
The ascent of the atmosphere is an opinion
which is further strengthened by the observations
made by MONS. CHARLES, in the car of
his balloon, at the time he was at the elevation
of 9,000 feet from the surface of the earth : he
observed, with great surprise, that the streamers
of his banners pointed upwards ; which, he
says, could not be the effect of the ascent, or
descent, of the balloon, as it was moving at the
time in an horizontal direction.
That a regular and progressive diminution
takes place of the atmospheric column, from
bottom to top, is proved by facts the most decisive
and satisfactory that can be devised ; it is
proved by the change which is produced on a
small quantity of atmospherical air, taken near
the surface of the earth, and carried in a bladder
to the highest point of elevation ; -the air
in the bladder is gradually found to dilate
and expand, as it does under an exhausted
receiver; insomuch, that the bladder which
284 PRESSURE IN THE AIR,
was shrivelled and fiacced, becomes round and
tense ; this effect was particularly noticed b^
Mr. BALDWIN, in one of his aerial excursions ;
he found in his ascent, that some bladders, tied
up with small portions of air in them, crackled
and expanded very considerably. The fact is
proved, by what takes place in the balloon itself;
although it appears near the surface of
the earth loose and flacced, in consequence of
not being so completely filled as it would admit;
it is seen gradually to swell and to dilate,
when it ascends to high points of elevation,
insomuch, that if a portion of the air which it
contained, were not allowed to get out of it, by
means of an aperture, constructed for that purpose
; such is the increased power of .expanding
which the air within has acquired, in consequence
of diminished resistance of the air
without, that it would burst the sides of the
balloon, and escape from its ^confinement ; as it
is found to do when it is confined in a glas
vessel, or bladder, under an exhausted receiver.
The diminution of atmospheric pressure at
high points of elevation, wras further proved by
SAUSSURK, in his ascent to the top of mount
Blanc ; not only by the great inconveniency
which he experienced in his own person, but
by the small report which a pistol fired in that
situation produced on his auditory nerves.
AND EXTERNAL RESISTANCE,
His respiration became difficult, his pulse
quick, and he was seized with symptoms of
fever; and the report of the pistol was not
heard in a greater degree, than would have
been produced by the discharge of a child’s
toy-gun near the surface of the earth. The
same effects take place upon the clapper of a
bell ; when forcibly struck against the sides,
it excites to the ear no more sound, than it is
found to do under a receiver, after a great portion
of the air it contained has been exhausted
out of it.*
* That the expansible force of the air, is the agent by
which sound is propagated and conveyed from a sonorous
body to distant objects, is decidedly proved by the cessation
of all sound in an exhausted medium. If a bell be placed
under a receiver full of air, and the clapper made to strike
against the sides of the bell ; the sound will\J)e immediately
propagated through the receiver, so as to be distinctly heard
by the bystanders ; and the sound will be found to increase
in degree, in proportion to the condensation which the air has
undergone. If a second receirer, however, be put over the
first, and the air be exhausted out of it; although the bell
within the first receiver be struck the same as before, no sound
will be heard ; we are led from thence to conclude, not only
that the pulsations of the air, are the agents by which sound
is communicated to the auditory nerves, but to understand
why it is more perfect in a dry, than in a wet day ; in a calm,
than in a storm ; in an atmosphere which is serene and clear,
than when it is foggy and wet ; finally, more perfect near the
surface of the earth, than at the top of the highest mountain.
286 PRESSURE IN THE AlK,
The facts which I have advanced are, I trus*,
amply sufficient to show that there is a pro-
The diminution of atmospheric pressure at different points
of elevation, is equally proved by the different degrees of depression
which mercury, in a torrecilian tnbe, is found to
undergo ; the experiment on this subject, which was first
suggested by DESCARTES, and put in execution by PERKIER,
although made for the express purpose of measuring the
weight of the air, proves, in a manner, sufficiently satisfactory,
the progressive diminution of expansive pressure,
which the atmosphere sustains from the bottom to the top, in
consequence of increased dilatation. Mons. Perrier, so long
ago as the year l64>6, filled two tubes, of an equal bore, with
mercury, and observed the height of it in both to be the same,
viz. 26-24 inches French, in the garden of the convent of the
Friars Minins^ situated in the lowest part of Clermont ; ort
leaving one of the barometers at the bottom of the garden,
and one of the fathers to observe it, he took the other one to
the Puy de domme, which was elevated near 500 French
fathoms above the garden, and found its height to be only
23 2-11 inches. On his return to the town, as he descended
he found, at 150 fathoms above the garden, that is 350 below
the upper station, that the mercury had risen to 25 inches ; and
on descending to the plain, he found that it rose to the same
level as the one which he had left in the garden, and which
had not varied the whole of the day. Thus a difference of
elevation of 3,000 French feet, had occasioned a depression
of 3 1-18 French inches: from which it maybe concluded,
not that 3 1-18 inches of mercury weigh as much as 3000 feet
of air ; or one-tenth of an inch of mercury, as much as
96 feet of air; but that the expansive power of air diminishes
in proportion to its dilatation ; the mercury in the*
tube sinking in the same manner as it is found to do, whew
AND EXTERNAL RESISTANCE. 287
gressive diminution in the density of the atmosphere,
from the bottom to the top ; I shall now
proceed to prove, that the increased power of
expanding which the atmosphere possesses,
from the top to the bottom, does not proceed
from the weight of the superincumbent column.
In order to make the case as clear as possible,
I shall trace back my steps, and proceed in an
inverse order to that which I have hither pursued.
- If a cubic foot of rarified air, at the highest
points of elevation, were received and inclosed
in a bladder of the same dimension, and carried
to the bottom ; it will be found to undergo a
change the very opposite, to that which a bladder
half full of air, taken near the surface, was
found to do, when it was carried to high points
placed in the receiver and the air which the receiver contained
exhausted out of it. Although the depression of the
mercury at different points of elevation, is not a test of the
different degrees of weight which the atmosphere possesses, it
certainly is of the progressive diminution of the expansible
power; and as it takes place in a manner which appears
(under the same state of the atmosphere) to be very regular
and progressive we may, from thence, employ the fall of the
mercury, as a measure of different degrees ofelevation. The
conclusions which were made respecting the weight, will be
the same, as if they had been made to prove the difference of
expansible power ; the only difference will be, that the conclusion
in the one case will be from a true, instead of proceeding
from false principles.
288 PRESSURE IN THE AIR,
of elevation: instead of swelling and dilating,
it is found, in the descent, to contract and collapse
into a smaller volume. There can be no
doubt that the condensation? which has thu&
taken place, has been produced by the pressure
of the external air, having overcome the
resistance of the rarified air, which the bladder
contained,
- In like manner, if two hollow hemispheres^
whose cavity is equal to one cubic foot, after
having had the air which they contained, exhausted
out of them, had the same quantity of
this rarified air introduced within them ; it is
very obvious that the external air would press
against the hemispheres, as it did against the
bladder, and keep them together in close COG^
tact.
- If this rarified air were introduced within
an exhausted receiver, to which the external
air could not obtain access, it is very clear that
the external pressure of the air must fix the receiver
to the pump-plate.
- That if this rarified air were introduced
into an exhausted cylinder, covered over with
a bladder ; that the bladder would be pressed
upon by the external air, and depressed into
the cylinder.
- That if this rarified air Were introduced
into an exhausted tube, which was placed upon
any fluid whatever, whether water or mercury,
AND EXTERNAL RESISTANCE. 289
is of no consequence ; it must be equally obvious,
that the resistance within, not being
equal to the pressure without, the fluid would
necessarily be forced up the tube, until the condensation
of the air within it was equal to the
air without it, and an equilibrium obtained; and
we may a fortiori conclude, that the degree of
elevation of the fluid within the tube would increase
in proportion to the degree of rarefaction
which could be accomplished.
- It is obvious, that by the abstraction of the
air, as far as was possible, out of the vessels men.
tioned, the diminished pressure within, which
was in consequence produced, would enable the
external pressure upon them from without, prc
gressively to increase ; the consequence would
be, that the glass receiver would be more firmly
fixed to the pump-plate ; that the bladder upon
the cylinder, instead of being simply depressed,
would be pressed upon with such an increased
force, that it would actually burst ; and that
the exhausted tube, whether made of glass,
iron, copper, or wood, immersed in the water,
or mercury, wotild have these fluids, by the
pressure of the external air, forced up to a
higher point of elevation than before, in the
unresisting medium which the tube contains.
It is owing to the same cause, to the dilatation
of the surrounding medium, that the va290
PRESSURE IN THE AIR,
cant space which is made by the passage of
moving bodies through the air, becomes immediately
filled ; and, finally, that the unresisting
medium which is produced in the cavity of
the thorax, in the class of mammalia, by the
elevation of the ribs, and depression of the
diaphragm ; enables the expansible power of
the air to enter the mouth and nostrils, to
fill and distend the bronchia of the lungs, and
to accomplish the process of inspiration to
accomplish it, with as much perfection in those
animals which descend from the upper regions
of the air, as it does in those that ascend up to.
them ; in an ass, whose mouth is pinned
down to the surface of the earth, as it is in a
whale, which receives the air from the upper
surface of the water.
Although we possess no means of obtaining
atmospherical air, at the highest points of elevation,
in a state of the utmost dilatation, we>
nevertheless, can imitate by art the same state
of rarefaction, near the surface of the earth, as
the air, probably, undergoes in the upper regions
of the firmament. However varied the
means may be, the object is the same ;
whether .that rarefaction be accomplished
by an exhausting syringe, according to Mr.
BOYLE’S plan, whether by filling a tube with
mercury, as TORHICKLLI did ; or by the aid of
AND EXTERNAL RESISTANCE. 291
an air-pump, as was adopted by OTTO GUERICKE.
The question itself is one of the more
or the less, and is a fit object for the inquiry of
the mechanic, in order that he may bring the
machine to its utmost state oLperfection ; its
excellence depending upon the degree of exhaustion
which it is able to produce.
When the degree of exhaustion has been
accomplished as far as it is capable ; the pressure
from without which the vessel sustains,
ma\r be considered a measure of the expansible
force of the atmosphere, with relation to the
unresisting medium within. Under these circumstances,
the Magdeburgh hemispheres of
three inches and a half diameter, require a
weight suspended from them of 140 pounds,
before the one can be separated from the
other; and Otto Guericke, in prosecuting this
experiment on a large scale, it is said, made
them to such an extent, and exhausted the
air within them so completely, that it required
the power of twenty horses, before the one
hemisphere could be separated from the other.
A thin glass bottle, exhausted of air, will
burst, in consequence of the pressure of the
atmosphere, as readily as it will do, when
full of air, arid placed under an exhausted receiver,
the only difference will be, that in
one case it will burst from without, in the
u 2
292 PRESSURE IN THE AIRy
other from within. In like manner, the receiver
of the air-pump will be immoveably
fixed to the pump-plate ; the bladder with
with which the cylinder may have been covered,
will burst, as soon as the air within is
exhausted; mercury will be forced up an exhausted
tube to the elevation of 29 or 30
inches, and water as high as 34 or 35 feet.
Although the effects which I have above
enumerated, and a multitude of others of the
same kind, evidently appear to me to be caused
by the expansible force of the air without, in
consequence of diminished resistance from a
high state of rarefaction within, and in which
the supposed weight of the atmosphere has no
concern ; I must be permitted to express my
surprise, that these phenomena, on the contrary,
are referred (by experimental philosophers
in general,) to the force of the incumbent
weight of the air, and not to its expansibility.
In order to decide the point with as much
accuracy as the subject will admit, and to
prove that it is not caused by the gravity or
weight of the atmosphere, I subjected them
to the test of experiments, in themselves so
simple, but, at the same time, so satisfactory,
that I flatter myself they will cause
the same conviction in others, as they have
AND EXTERNAL RESISTANCE. 293
done in me. I shall, therefore, proceed to show,
that the various phenomena which take place
by the mechanical power of the air, are not
referable to its weight, but to its expansible
power alone.
L It must evidently appear, that if it be the
weight of the air which, in one instance, pressed
and kept the Magdeburgh hemispheres,
when exhausted of air, by a bond so close and
firm, &s to be equal to a weight of 140 pounds,
and in the other to a power of 20 horses, before
they could be separated ; it must require
a weight equal to that force to compress them.
So far, however, from that being the case, I
placed, as many have done before rne, the
common hemispheres under a glass-receiver,
containing four cubic feet of air, the weight of
which in vacuo did not amount to one drachm,
and from which the atmospherical air, external
to the receiver, was entirely excluded; the
firmness of union by which they were held
together in the open air, did not appear to
be in the least abated, although exposed within
the receiver to a weight so extremely small.
On exhausting, however, that small quantity of
air out of the receiver, and rarifying thereby
the air without to the same state as it was
within, the one hemisphere immediately separated
from the other. If the same hemispheres
294 PRESSURE IN THE AIR,
be placed under the receiver of an air-pump,
without exhausting the air out of them, and
double the quantity of air be thrown into the
same space, it will require a double force to
separate them, so that a double atmosphere
has the same advantage over a single one, as a
single one has over an exhausted one.*
- In order to prove that the rupture of the
* It is to GALILEO, a celebrated mathematician of Pisa,
in Italy, that the error of measuring air by weight is to
be referred. He advanced (and maintained it to be an undeniable
truth) both in philosophy and mechanics, that no heavy
body ascended, without another heavy body descending as a
counterpoise to it ; he was the first who supported and suggested
the doctrine, that preternatural ascent of fluids arose from a
regular and natural cause in the weight and pressure of the air.
It was this hint which led TORRICELLIUS, of Florence, in
1643, to perform a variety of experiments, with a view of
ascertaining the weight of the air, and to form the first rough
model of a barometer ; he constructed a tube 60feet hi length,
which he afterwards reduced to 40, by suspending it in water,
and by means of a sucker attached to the upper part of it, on
exhausting the air out of it he found that the water followed
the sucker, and rose to 32 33 feet, but no art whatever could
elevate it beyond 38 or 40 feet. Such was the unweildiness
of the instrument, that it required the sails of a windmill to
invert the tube : he therefore availed himself of the mean and
relative weight which mercury bore to water, so that by substituting
mercury for water, he was enabled to reduce the
length of the instrument from 40 feet to 33 inches.
AND EXTERNAL RESISTANCE, 295
bladder, with which an exhausted receiver is
covered, is not caused by weight or the per*
pendicular pressure downwards of gravitating
or ponderable air, is proved by the bladder
bursting with as much facility if it be exposed
to the lateral, as to the perpendicular pressure,
upwards as downwards. To decide the point,
however with the utmost accuracy, I placed a
small cylinder, having
a bladder closely
tied over its top,
upon an exhausting
pump ; and over the
cylinder thus capped,
a receiver ; so
that there were between
the receiver
and the cylinder,
six cubic inches of
atmospherical air,
weighing about 10 grains, from which the external
air was entirely excluded. On exhausting
the air out of the cylinder, the bladder with
which it was covered, burst with as much facility
by the force of those 10 grains of air, as
it does when exposed to the influence of the
whole weight which it is supposed the column
of atmosphere exerts on the surface. If weight
.therefore, be the cause, of which the bursting296
PRESSURE IN THE Allt,
of the bladder was the effect, it must unavoidably
follow, that this effect was accomplished
from the weight of the air between the cylinder
and the receiver, and which before was ascertained
to amount to 10 grains only. On placing,
howeVer, a weight over the bladder, not of
10 grains, but of 18 pounds, it was found capable
of supporting it, without suffering any lesion
whatever.
As the weight placed upon the bladder covering
a full receiver, may not be considered
to be under the same circumstances as it is,
when the air is exhausted out of it; and with a
view of ascertaining what degree of weight is
absolutely necessary to burst the bladder, abstractedly
from the air ; I stretched a bladder
upon an open frame, and placed upon it a
weight of 18 pounds, and over it a receiver;
on exhausting the air out of the receiver, the
bladder was enabled to support the weight,
without being ruptured, equally well as if it
had been exposed to the open air. It is, therefore,
legitimate to conclude, that although the
effect produced, the bursting of a bladder over
an exhausted receiver, is caused by the pressure
of the air, yet, that it is not caused by the
pressure of weight, but is to be referred to the
pressure of expansibility alone, which air has
been proved to possess ; which expansibility is
AND EXTERNAL RESISTANCE. 297
Universally exerted, whenever the equilibrium
is destroyed, and where the least resistance
prevails.
I have deemed it proper to dwell at some
length on this part of the subject,, in order
that I might put it on its proper footing, and
explain away the improper notions to which it
has given rise; notions which have led to the
most erroneous conclusions to the erroneous
suppositions that it is the weight, and not the
expansibility of the air or atmosphere, which
causes the elevation of the mercury in the Torricellian
vacuum as it is called, as well as that
it is not the expansibility, but the weight of the
air, that causes the depression and rupture of
the bladder over an exhausted receiver; when
in fact the weight of the air is no more concerned
in elevating the one, than in cracking the
other.
In order to prove the fact, I placed and immersed
the bottom of a Torricellian tube in a
basin of quicksilver, and placed a receiver
over it ; in the top of the receiver, a screw
was inserted, with a stop-cock attached to
a bladder, which had been previously filled
with common atmospherical air, as nearly
as possible of the same dimensions with those
298 PRESSURE IN THE AIU,
of the receiver
itself; the
volume of air
amounting to 2
feet, the weight
ofwhich might
amount to 30
grains. The
whole apparatus,
therefore^
consisted <H
a Torricellia
tube filled withV <^
quicksilver in v
the usual way,
placed under the
receiver. On
exhausting the
air out of the
receiver, the
mercury in the
tube immediately
sunk to
the. same lev el
as the mercury in the basin. By turning the
stop-cocks, the air which the bladder contained
immediately passed into the receiver; the effects
of which were rendered evident, by the
alteration which the mercury in the basin underwent
; the mercury which before was at the
AND EXTERNAL RESISTANCE. 299
bottom of the tube, at the same level with that
in the basin, immediately ascended in the exhausted
and unresisting medium which the
Torricellian tube contained, to the elevation
of 29|- inches, being of the same level as one
exposed to the open air. It must, therefore,
follow, that if the elevation of the mercury
under the receiver was the consequence of
weight, it must have been accomplished by
the weight of the air which had passed from
the bladder into the receiver, and which before
I had ascertained to have amounted to 30
grains only. With a view of seeing whether the
same weight of ponderable matter, lead for instance,
would have the power ofelevating themercury
from the basin into the tube, I placed 100
grains of lead on the mercury in the basin; on
exhausting the air out of the receiver, so far
from that weight of lead being adequate to preserve
the mercury in the tube to the same elevation,
as the pressure produced by one tenth
part of the same weight of air ; I found, on
exhausting’ the air out of the receiver, that the
mercury in the tube sunk to the same level as
the mercury in the basin. I endeavoured to
ascertain what quantity of weight was adequate
to raise the mercury in the tube exposed to the
open air above the standard it was then of 29J
inches. I, therefore, placed a piece of pasteboard
over the mercurv in the basin, as well
300 PRESSURE IN THE AIR,
adjusted as was possible, having an aperture
for the passage of the tube, and found that it
required the additional weight of 10 ounces and
6 drachms to raise the mercury in the tube one
quarter of an inch, that is to say, from 29^
inches, to 29f. With a view of varying these
experiments, and to obtain additional evidence,
that it is the pressure of expansibility
and not the pressure of weight which air exerts
when the equilibrium is destroyed, as is the case
in exhausted media in general, and in the Torricellian
vacuum, as it is improperly called, in
particular; I took equal and separate portions
of different gases, whose relative weights are
Jknown to be different from each other, I inclosed
each gas separately in each bladder, and
screwed the bladder as before to the receiver in
which the Torricellian tube was placed ; one
bladder contained hydrogen gas, 2nd, oxygen
gas, 3rd, atmospherical air, and 4th, carbonic
acid gas ; the tubes were of the same lengths,
but the’ bores were different ; varying in size,
from % of an inch, to 1 inch in diameter.
On exhausting the air which the receiver contained,
the mercury in all sunk in the same
time from 29^- inches to the same level as the
mercury in the basin : on admitting each gas
to each tube, it was uniformly found, that neither
the difference in the weight of the gas, nor
the difference of the bore in the tube, produced
AND EXTERNAL RESISTANCE. 301
any difference whatever in the elevation of the
mercury. It was found that pure hydrogen
gas, which is considered to be 13 times lighter
than atmospherical air, was able to raise the
mercury from its level in the basin to 29^
inches, equally and as rapidly as either the oxygen
or atmospherical air, and more especially as
the carbonic acid gas, which is the most ponderable
of the whole; and that the size of the tube,
and consequently the quantity of mercury in it
to be raised made no difference whatever ; the
mercury in the smallest tube did not rise faster
or ascend higher than the mercury in the largest.
Although I had not the means of pushing
the experiment to a greater length, than that of
raising 30lb weight of mercury with four pints
of hydrogen gas, which do not weigh 2 grains,
I have every reason to believe that these 2 grains
weight of hydrogen gas would be capable of
elevating, and of preserving in a state of suspension
to the height of 29 inches in an exhausted
tube, a quantity of mercury of the greatest
magnitude. To those, indeed, who are not
disposed to ascribe the elevation of the mercury
in an exhausted tube, or water in exhausted
pumps, to the expansible power of the
external air, I would recommend them to as^
certain the fact by the easiest of possible means.
It may be proved by simply placing two instru302
PRESSURE IN THE AIR,
ments, improperly called barometers* under
different states of atmospherical influence ; the
one under a glass receiver from which the external
air is entirely excluded, containing* any
quantity of air, say 2 cubic feet, weighing 25
or 30 grains ; the other in open space, exposed
to the influence of the whole atmospherical
column; it must evidently follow, that if the
elevation of the mercury in the tube be caused
by weight, by the pressure of weight of the atmosphere
; the mercury in the tube of each
instrument ought to undergo unequal degrees
of elevation ; so far, however, from the elevation
being unequal, the mercury will be
found to preserve the same parallel in both.
The preservation of the mercury to the same
parallel in two instruments placed in situations
so totally different from each other, either proves
*
Properly speaking, a barometer is a measurer of weight
only, and consists of a pair of scales with a weight in one
balance, with a view of measuring the pressure of weight
produced by the matter contained in the other ; and the barometer,
as now constructed, may be employed for the same
purpose; it may be employed also as an excellent measure,
for ascertaining the relative effect produced by weight, and
the pressure produced by expansibility, as well as between
the relative degrees of expansible pressure, which are exerted
by different gaseous fluids. In every case, the degree of elevation
of the mercury in the tube will be the sum of the
pressure produced.
AND EXTERNAL RESISTANCE. 303
the absurdity, that equal effects can be produced
by unequal causes, or that the weight of 25
or 30 grains can accomplish as much as the
whole incumbent weight which the atmosphere
is falsely supposed to possess : if the receiver,
with which the first instrument was covered,
be removed, and exposed to that supposed
weight, the mercury within it continues unaltered.
The conclusion, therefore, presses upon
the mind with force irresistible, that the elevation
of the mercury in the Torricellian tube,
and the various degrees of elevation and depression
which it undergoes, are not caused
, by the weight or gravity of the air ; and
that the weather-glass now in general use,
called barometer, from 0f nfyov, a meter or
measurer of weight, is called by a term
which is irrelevant and improper, but that
the term ana-plometer, from the compound
word avaKKou ftfyov, a meter or measurer of expansibility,
ought to be substituted for it. So far,
therefore, from the barometer measuring the
degree of pressure which the atmosphere exerts
by its weight, it is by its expansibility alone
that the atmosphere acts, pressing with the
greatest force when it is least ponderable, and
when it is most ponderable exerting the least
pressure; that is to say, that it is most expansible
when least ponderable, and least ponderable
when most expansible.
During the various discussions which I have
304 PRESSURE IN THE AIR,.
had upon this subject with men of science, I
have been much amused with the various arguments
they have employed, and with the different
false facts which they have advanced, in
order to invalidate the force of these experiments.
Tt was said by one, that instead of
employing a bladder of the same size as the
receiver, a glass globe ought to have been
used ; and in that case, on letting in the air
from the globe into the receiver, the mercury,,
instead of rising to 29 inches, would only have
risen to half that height. Nothing can be morecertain,
and the reason is most obvious ; instead
of the air which was contained in the
globe being altogether transmitted from it into
the receiver only, as it is from the bladder, the
air would fill the globe and the receiver together;
and in consequence of the increased dilatation
which the two cubic feet of air underwent, by
occupying the spajce of four feet, contained by
the globe and the receiver together, instead of
two, the expansible force of the air must be
diminished in proportion, and the mercury, instead
of being forced up to 29 inches, would
only rise to 14^. A second very judiciously
observed, at the time I was making some experiments
on the subject, that I only exhausted a
given quantity of air out of the receiver, which
sunk the mercury to the same level as the mercury
in the basin, and merely restored the same
AND EXTERNAL RESISTANCE. 303
column of air from the bladder back into the
receiver, which, consequently^ rose the mercury
as high as before. The observation was a
very just one, but it did not apply to the ob*
jection which he wanted to make ; for although
it was very true, that the same given quantity
of air entered into the receiver, as had been
pumped out of it, a separation existed, total
and complete, between the air in the receiver,
and the column of air external to it, if it were
therefore, the weight of the air, which forced
up the mercury in the tube, it could only be
the actual weight of the air alone which the
receiver contained, a weight of 20 grains, elevating
to the height of 29 or 30 inches, a column
of mercury of the weight of 30 Ibs. ! ! !” A third
sagaciously remarked,
” I do not pretend to
say, that it is the absolute weight of the air,
which causes the elevation of the mercury, but
it is owing to the regular and progressive increase
of weight, which the whole column acquires,
that the elastic, or expansible, foree of
air is increased at the bottom!!!” And this
knock me down argument, was supposed to be
proved, by an illustration which was made by
a fourth ;
” Take (he said) a spiral spring of
*ny height, place it on the mercury in th baion
apply a given force upon it, to overcome
the weight of the mercury, and the mercury
jnay by that means be raised to any given
x
PRESSURE IN THE AIR,
height ; run a nail through any part of the
spring hammer and fix it to a post, and cut
off the upper part of the spring, and the mercury
will be found to continue, by the pressure
of the inferior portion, as high as it was
before!!!” The distinction which I have
shewn to exist between expansibility between
elasticity and between weight, will, I
hope, show the error and futility of these observations
; the most elastic substance which
exists, whether steel or whalebone, is not elastic
per se ; if it presses at all, it presses by its
quantity only, either of gravity or of levity ;
when it presses by an elastic force, it is in
consequence of a power which has been externally
applied to it, by virtue of which the particles
of matter become compacted and compressed,
in proportion to the degree of external
power which has been employed ; the resistance
of the steel may prevent the force employed,
from extending beyond the first, or
second circle, or it may be so great as to overcome
the resistance of all the circles of the
spring altogether, and cause pressure to be produced
at the other extremity of the spring,
which pressure will make the mercury rise:
it will rise in proportion to the external force
employed ; and it will be kept at that point, if
the weight of the steel is sufficiently heavy to
balance the mercury, or the force sufficiently
AND EXTERNAL RESISTANCE. 307
great to raise it. The elastic force whicfr
the steel has acquired, is entirely from without
; and it ceases the instant that force is
taken away -the external force is the agent,
the steel is the instrument only; and it is by
the combination of both together that the effect
is produced ; the one without the other is uur
equal to the task.
With respect to expansible bodies such as
air, it is far otherwise ; it contains within itself
both the agent and the instrument instead of
acting, like elastic bodies, mediately it act$
immediately although an external force may
jcompress and condense it, into a smaller volume
; it was expansible before that external
force was applied. It acts, by its own inherent
power, independently of external influence,
wherever the least resistance prevails; and,
consequently, overcomes the weight of the mercury,
when it is placed at the bottom of a tube,
having in it an unresisting, because an exhausted
medium. It is becausethere is less resistance
in the medium above, than there is below that
the natural tendency in the air of expanding
equally in every direction, is rather directed
and diverted from the bottom towards the top;
that, the air, rather ascends than descends ;
and, consequently, that the observation made
by the former gentleman, is an erroneous one
” that the whole weight of the incumbent colunm
308 PRESSURE IN THE AIR,
of air, is the cause of its elastic force being
greater at the surface, than at the top.” It
appears to me, as far as I am able to comprehend
Mr. DALTON’S opinion upon this
subject, that we think very much alike. It is
His opinion, that the different gases, which constitute
the mass of our atmosphere, are mechanically
combined together; arid this, he conceives
accounts for the uniformity with which they are
mixed together in it, first, because the particles
of any individual gas, repel each other;
and secondly, because the particles of mixed
gases, neither attract nor repel each other ; they
are perfectly indifferent to each other, and are
not affected by their mutual proximity. When
they are mixed, they are diffused and joined
together, without separating, or uniting. Every
gas, by its elasticity,* or the repulsion of its
particles diffuses itself over the space in which
it is confined, neither attracting or repelling
each other, and therefore mixes without uniting
together. If, for example, there subsists on
the surfac^ of the earth, a column of oxygen
gas, it will rise to an indefinite height by its
elasticity ; if on the same surface, it be sup-
* It is really vexatious to see the best informed of our
philosophers, ignorant of the distinction which exists between
things, and, consequently, using false terms to express the
phenomena which they want to describe !
AND EXTERNAL RESISTANCE. 309
posed there rests a column of nitrogen gas, its
particles will equally recede, and become intimately
mixed with those of the oxygen gas.
Other gases, as caloric, or watery vapor, may be
thrown in, and the same arrangement of their
particles will take place, and thus on the
earth’s surface, there will rest so many columns
of gases, each intimately blended indifferent
to each other each supporting itself by its own
elastic power, and the inferior strata of each
only pressed by their own incumbent weight.
It is owing to the ignorance of the difference
which exists between expansibility and elasticity,
that many have been led to contend, that
unless two fixed points existed, it was impossible
for expansible bodies to expand ; the fact
is unquestionably true, with respect to elastic
bodies as they are called, but not with respect to
those that are expansible, expansible bodies
manifest their power without them -elastic bodies
derive the whole of their power from them.
A piece of steel, is only elastic through the medium
of compression at both ends. Air is expansible
at all points. The steam ofwater does not
derive its expansible force from the resistance
which it overcomes, from the sides of the kettle
in which it is enclosed the steam possesses
this expansible power without their influence;
it is the pressure of the steam which is able
MO PRESSURE: IN THE AIR,
to overcome the resistance of the sides of the
vessel in which it is contained.*
If we proceed to ascertain the relative
weights of equal volumes of atmospheric air,
when they subsist in the form of rain, or in a
dry state ; it will be found that the weight, and
inelasticity of the one, will far exceed the levity
and expansibility of the other.
It is to the error of measuring air by
weight, instead of expansibility ; and of subjecting
tb the same laws bodies whose nature
and properties were totally different
from each other, that a great proportion
of the false philosophy of the present day
is to be ascribed ; it was in subservience
to this false philosophy, of measuring air
by weight, that Mr. BOYLE himself, so deservedly
esteemed for eviery quality that was great
and good, in order to account for the rise and
* Pressure and resistance are words which are often confounded
together, but which, nevertheless, have opposite
meanings. Pressure is an active force Resistance a passive
quality. Thus, when I press my hand against the door, my
hand is active, the door passive. A horse which draws a cart,
is active, the cart passive. The difference in the nature of
each, may, perhaps, be better explained, by comparing resistance
with pressure, than pressure with resistance. The
door cannot press and squeeze my hand, although it can
resist the pressure ; it cannot act upon it, although it may be
acted upon by it. The cart cannot act upon the horse, although
it may resist the horse ; the one may, in fact, be
considered an active, the other a negative quality.
AND EXTERNAL RESISTANCE. 311
fall of the mercury in the Anaplometer, by the
known changes which the atmosphere undergoes,
concluded, that the weight of the atmosphere
was greatest when it was most serene and
clear ; and, on the contrary, that it was most
light, when most thick and cloudy and charged
with vapours ; that is to say, that it was most
heavy when it was most light, and most light
when it was most heavy ; the mercury rising
in the former case from 26 to 30 inches ; and,
on the contrary, settling in the other from 30
to 26 inches.
It was owing to the same errors from which
conclusions have been drawn, revolting to the
feelings and to the senses of the most ignorant,
that the pressure of the atmosphere upon bodies
situated near the surface of the earth, was the
pressure of weight, not of expansibility; and
that the weight of the incumbent column was
said to be the cause of that compression ; insomuch,
that if there were a pit dug in the bowels
of the earth, 33 miles in depth, the air at
the bottom would be as dense as water, but if
it were 50 miles deep, the air would, in that
case, be as dense as gold itself. It was in furtherance
of this false philosophy, that it was
affirmed, and continues to be believed at this
time as a true article of philosophical faith,
that the absolute weight, or perpendicular pressure
downwards of the atmospheric column
312 PRESSURE IN THE AIR,
from the top to the bottom, is in the proportion
of 15 or 16 Ibs. to every square inch of surfaceand
as there are 144 square inches to every
square foot, these :must consequently sustain a
pressure of weight equal to 2,880 Ibs. supposing,
therefore, that a man in an erect posture covers
a surface commensurate to a square of 16
inches, (a calculation very moderate,) it must, in
that case, follow, that the perpendicular pressure
upon him, is equal in weight to 2,880 Ibs.
But, alas ! if he should have lips thick nose
flatcheek-bones prominent ears expanded
hat broad-brimmed, a parasol to keep off the
sun, or a parapluie to shelter him from the rain,
the weight must, in that case, be as great, as
it is when he is in a recumbent position ; or
when the superficies of his body may be consequently
supposed to be increased, at least, to a
square of eight feet; it is affirmed, and very
justly affirmed, if the positions were true from
which these conclusions are drawn, that such
a one must sustain a weight of 15,370 Ibs. that
is to say, more than seven tons weight, for his
Ordinary load!!! It was from data such as
these, that Mr. COTES, and others, conceived
that they had been able, with precision, to calculate
the absolute pressure of dead weight of
the whole ambient air, impending over the
globe in general, and this country in particular.
The superficial surface of England, is
AND EXTERNAL RESISTANCE. 313
-estimated at 39 millions of acres, the weight
of the atmosphere upon it, ought consequently,
to press with a force equal to
fifteen hundred thousand millions of tons,
(1,576,870,000) and the weight upon the whole
surface of the world, is estimated to be equal
to a globe of solid lead, 60 miles in diameter.
Whatever reprehension such conceits might
merit, if they were merely intended to astonish
the ignorant, by an idle display of the wonderful
powers possessed by natural means, they
become absolutely ridiculous, and laughable,
when they are maintained as fundamental
truths by the wisest of the wise.
In order that the fanciful consequences which
have been so learnedly described, should ensue,
the natural condition of things as it actually
exists, must be destroyed, aad an inverted
state of it, be fancied and whimmed ; instead
of the atmosphere subsisting in a state of equilibrium,
it ought to press ^unequally in particular
directions ; ipstead of subsisting in
open space, it ought to be confined in close
vessels ; instead of being denser at bottom
than at top, it ought to be denser at top thai*
at bottom ; and, finally, instead of moving, as
we do in a plenum, we ought to move and to
breathe (if I may be allowed the folly of sucfh an
expression) in a perfect and a perpetual vacuum.
If this inverted order of nature, and of
314 PRESSURE IK THE Alfc,
things, actually were what it actually is not ;
the various estimates which I have above detailed,
might then be applied. Mr. Cote’s calculation
might be true, that the circumambient
air, was in weight, upon the surface of the
earth, equal to a leaden globe 60 miles in diameter
; and that \he weight of 15,370 Ibs. pressed
on our frail and debile bodies. It must,
however, be evident, that a weight such as this,
would lacerate to atoms the lungs of all animated
beings ; and explode every part of the
system to which it obtained admission that
the fluids would be pressed and squeezed out
of the exhalent vessels, and that air would
issue out of every pore.* So far, therefore,
from measuring by its weight, the degree of
pressure which the atmosphere exerts, it is
by its expansibility alone, that its effects are
produced, pressing with the greatest force
when it is least ponderable, and when it is
most ponderable, Exerting the least pressure;
that is to say, air is most expansible when least
ponderable ; and least ponderable, when most
expansible. That this is the fact will appear,
if we proceed to ascertain the relative weights
of equal volumes of atmospheric air, when they
* I beg to have it understood, that these calculations are not
my own, but those of others, which I offer in order to show
how true conclusions can be drawn from false principles, and
error substituted for truth.
AND EXTERNAL RESISTANCE. 313
Subsist in a vaporific, or gaseous form, in the
form of rain, or in a dry state : it will be found
that the weight and inelasticity of the one, will
far exceed the levity and expansibility of the
other : in the one case, the mercury in the tube
sinks in the other it rises, while the degree of
depression of the mercury is found in a great
measure to depend on the decompositions,
which the atmosphere undergoes, from dryness
to moisture from a calm to a storm ; its elevation,
on the contrary, proportionably takes
place, from moisture to dryness from astorm to
a calm. From the experiment of Perrier, which
I have detailed, and which has been repeated
by different metereologists, it appears, that the
elevation of the Anaplometer, to 3,000 French
feet, from the surface of the earth, occasioned
a depression 3:1-8 French inches of the mercury;
from whence it was concluded, that
3 : 1-8 inches of mercury, weigh as much as
3000 feet of air, and 1-10 f an inch of mercury,
as much as 96 feet of air ; when, therefore,
the mercury stands at 30 inches, near the
sea shore, it is conjectured, that, if it were
raised to 300 times 96 feet, or a little more
than five miles, the mercury in the tube would
sink to the same level in the basin, as it is
found to do, in the
receiy^,
after the greatest
portion of air which it captained, has been exhausted
out of it. In order to make the calcu316
PRESSURE IN THE AIR,
lation as precise as possible, it is said, that as
the weight of air is to that of mercury, as 1 is
to 10-800, it must, of course, follow, that if
the weight of the atmosphere, be sufficient to
raise a column of mercury to the height of
30 inches, the whole atmospheric colum~
must be 10-800 greater in weight; and,
consequently, that the whole extent of the
atmosphere, from the bottom to the top, cannot
exceed five miles one quarter. After
the proofs which I have advanced, in order to
show that the elevation of the mercury in the
tube, does not proceed from the pressure of
weight, I shall merely observe, that these limits
were proved to be false, by the facts which the
authors themselves produced ; they were proved
to be false by the frequent appearances of
meteors, of those bodies which cannot exist
without the existence of air, at the elevation of
80 miles from the surface of the earth. In the
month of March, 1719, a meteor was seen, by
Dr.HALLEY,at the computed height of73 miles,
whose diameter was 2,800 yards, or upwards
of a mile and a half; and whose velocity
amounted to 350 miles in one minute. In latter
times meteors of a similar nature have been
observed, whose magnitude and motion, as well
as distance from the earth, was far more considerable.
The 18th of August, 1783, one of
these was discovered, whose distance from the
AND EXTERNAL RESISTANCE. 317
earth was estimated at 100 miles ; and whose
velocity was not less than 1000 miles in a minute
of time. The indefinite elevation to which
the atmosphere extends, is more especially
proved by comets, by those meteors which
surpass every other of which we have any
knowledge, in magnitude and motion, as well
as in brilliancy and transparency, the sun alone
excepted. Instead of being rounded, like common
meteors, they are, for the most part, distinguished
from all other bodies, by having a
large mass of matter attached to them, in consistency
so semitransparent, that the smallest
star can be distinguished through it, in color
smoky, or clouded, and in figure striated and
fibriated like hair ; it is from this peculiarity in
the appearance of this portion of the whole,
that the name of Comet has been derived, from
Coma-Hair.
When we reflect on the facts which I have
detailed, of the wonderful power of expanding
which air possesses, when external resistance is
weakened ; and more especially if the supposition
entertained by Sir I. NEWTON be true, that
a cubit foot of air, carried to the elevation of
one semidiameter from the surface of the earth,
would expand as far as the orb of the planet
Saturn, we are bound to believe, that the calculations
which have hitherto been made, and
which confine the elevation of the atmosphere
318 PRESSURE IN THE AIR,
to five miles only, are far too limited ; and 01*
the contrary, that it has the power of expanding
to an indefinite extent.
Instead of the different gases of which the
atmosphere is composed, obeying the lav of
relative weight,* they act in direct opposition
to it. If gases acted by virtue of their weight,
instead of the atmosphere being one united
whole, composed of parts, whose essential properties
are alike, but whose secondary, or chemical
qualities, are different ; it would consist
of separated parts, out of which one disjointed
and tesselated whole was formed. Instead of
being, as it is found to be, of one uniform
homogeneous nature, combined together in a
manner the most intimate and imperceptible
the parts would separate into different layers,
or strata the lightest would form the summit,
the heaviest gas the base of the whole : we
would have hydrogen at the top oxygen and
nitrogen in the middle, and carbonic acid at the
bottom. If we were to have what we actually
have not, the human race, in general,
* I beg to observe, that as there is no such thing as absolute
weight; and as weight is ever to be considered the measure
of the density of one body, with relation to the rarity of another,
the terms relative and absolute, ought to be entirely abandoned
; and that when we speak of a body being heavy, or
Jight, it is either dense, or rarer, than another one.
AND EXTERNAL RESISTANCE. 319
and herbivarous animals in particular, would
be suffocated and poisoned as effectually as if
they were exposed to the vapour of the grotto
del Cane, or of the lake of Averno. A beneficent
Providence has directed it otherwise : the
weight of different gases is entirely overcome,
by the equal degrees of expansible power
which they separately possess.
If the chemical properties of these gases are
examined, they will be found very different
from each other. The properties of nitrogen
would seem to be rather of a negative, than of
a positive nature; it is neither absorbed by
pure water, in any sensible quantity, neither
does it render lime-water turbid, or turn it
white, it produces no change in vegetable
color, and is totally unable either to support
combustion, or subserve to the process of respiration.
Oxygen, on the contrary, is the principal
agent in the production of combustion, and
when mixed in the proportion in which it is generally
found to exist in the atmosphere, is best
adapted to promote, and to subserve to the process
of respiration. It is obtained from different
substances, by factitious and unnatural
means ; it is disengaged by the operation of an
ardent fire, from nitre, from manganeze, and
other bodies, when closely confined in a retort.
It is very generally excreted during the day by
320 PRESSURE IN THE AIR,
vegetables in general, more especially when
they are exposed to the free influence of the
solar rays.*
Although it is very true, that vegetables, during
the day, excrete a quantity of this particular
gas ; they are known to absorb a large
proportion of it also. In the oxydation of metals,
the full quantity is separated from the
atmosphere, by the fire, as is given out by the
oxyde ; and the intensity of fire which it is necessary
to excite in order to obtain oxygen gas,
is not found to exist, in the ordinary state of
things. Means, therefore, such as these, are
altogether, inadequate and insufficient, to account
for the actual existence, much less for the
reproduction of the immense quantity of oxygen
gas which is perpetually separated from the
atmosphere by animals and vegetables, during
* If further evidence of the wretched state of our Nomenclature
were necessary, I should dwell particularly on the
term Oxygen Gas. Oxygen means sour, and is supposed to
comprehend the solid base, or gravitating matter, and the term
Qxygen Gas, the actual existence of this base, in a airiform
state ; it is imagined by chemists, that it forms the principle
of all acids, and of acid combinations ; and from this circumstance
it is, that its name is derived : it would, however, seem
very unscientific to call this gas, Oxygen gas, or sour gas,
when it neither is sour to the taste, or produces on other bodies
any of those effects which acids are prone to do, and bj
which they are distinguished from other bodies.
AND EXTERNAL RESISTANCE, 32 J
the process of respiration, and consumed in the
generation of ignition, and of combustion.
It is very probable that these means may form
a subordinate, and auxiliary part, i the production
of oxygen gas. The whole column of
the atmosphere, however, long before this advanced
period of the world, would have been
contaminated, and rendered unfit for the support
of animation, and the generation of ignition,
if there did not exist, in the great laboratory
of nature, some means, by whose agency
the whole chaotic mass, of which the atmosphere
is composed, both solid, liquid, and
gaseous,–animals in their living state, as
well as animal and vegetable exuviae, and poisons
the product of both, become purified
and regenerated through the process of decoraposition.
On a faithful review of the whole, it appears
most probable, that it is by the agency
of the solar rays, that this regeneration i
accomplished, and oxygen gas formed ia
the abundant quantity in which it is found.
It may, indeed, become a question, which
future experiments may solve, it may, I
say, become a question, whether the resolution
of particular parts of organised bodies^
both animal and vegetable, into hydrogen and
carbonic acid gas, may not be among the first
changes which these parts undergo, by the
322 PRESSURE IN THE AIR, ETC.
processes of putrefaction and fermentationthat,
as those parts are resolvable into these
gases, so these gases (in consequence of certain
processes to us unknown) may, in union with
oxygen gas, become convertible into that immense
mass of nitrogen, or azotic gas, of which
the greatest portion of the atmosphere is composed
;< that as animal and vegetable matter,
constitutes the base of hydrogen and carbonic
acid gas, so carbonic and hydrogen gas, may
constitute the base of nitrogen. The noxious
qualities which these gases separately possess,
become so neutralised, if I may be allowed
the expression, by the new combinations which
they have undergone, that they are ultimately
lost ; insomuch, that the atmosphere altogether
becomes fitted and adapted to answer the end
for which it is designed, the nourishment and
support of the animal and vegetable creation,
and the base from whence illumination, in general,
is produced, and color in particular
CHAPTER XVI.
ON COLORIFICATION IN GENERA^,
On the means % which Color is produced,
the sourcefrom whence it i$ Derived,
ALTHOUGH the art of analysis irj these latter
days has attained considerable degrees of perfection,
and a multitude of tests have been discovered,
by the aid of which, a variety of bodies
have been decomposed, and simplified to
a greater extent than before; it must, nevertheless,
be acknowledged, that none of the
skilful artists, who have labored in t)ie pursuit,
have as yet been able to exhibit to our view,
the real constitution of the primary particles of
matter; insomuch, that natural philosophers,
Sit this moment, either confess their total ignor
jrance, or are at variance with each other on
324 COLORIFICATION IN GENERAL.
subject. When we, however, reflect on the
actual state of things, as they exist in this world,
in which animated beings are fed and nourished,
not only by a large proportion of the common
matter of which it is composed, but by the
materials which are produced from the -decomposition
and corruption of living matter also ;
and that a variety of new combinations are constantly
taking place between the different parts,
every allowance ought unquestionably to be
made, for the imperfection which exists. It is>
probably, owing to an ignorance of the properties
which essentially belong to different species
of elementary matter, that attention has been
exclusively bestowed on those which are secondary
and accidental ; they are, in fact, those
which are most cognisable to our senses, and
which excite on them the sensations of hardness,
and of softness of figure, and of color
of flavor, and of sound of heat, and of cold.
It must not, however, be inferred, because
substances, various and extraneous, often alloy
gold, that the pure metal does not subsist in its
individual and virgin state ; or that light, water,
and earth, have not an elementary existence,,
because different bodies are generally found,
either chemically combined with them, or mechanically
diffused in them. A contrary conclusion
can only be formed from the false
trOLO&IFICATION IN GfcNE&AL. 325
Assumption, that the great first Cause, who
created the universe, and all that is therein,
created confusion before order imperfection
before perfection the compound before the
simple ; it is far otherwise ; all the secondary
qualities of bodies which exist, are produced
by the union and combination which take
place, from things simple and elementary : and
in order to have a scientific knowledge of the
phenomena which nature presents to our view ;
in order to know the causes of these phenomena,
(which are nothing more than effects produced,)
it is absolutely necessary, to have a clear apprehension
of the simple, before the con>
pound- of expansibility, before expansion of
fluidity, before solution of light, before color
of vitality, before organisation of extension
in general, before figure in particular. The
phenomena which the secondary properties of
matter display, are the means by which those
which are primary and essential are explored;
they are the steps by which we are enabled to
ascend from the last to the first of things,
from the effects, to a knowledge of the cause ;
a branch of knowledge which, it is probable, the
art of analysis cannot attain, because analysis
cannot resolve that which is irresolvable, but
which, nevertheless, may be apprehended by
abstraction and contemplation. The defective
COLORIFICATION IN GENERAL.
state of the analytic art, equally extends to the
synthetic ; although a multitude of compound
bodies, can factitiously be formed from those
that are simple ; no effort of human ingenuity,
has been able to discover the means by which
the pure colorless solar rays, in their passage
through the atmosphere, acquire properties
which are totally different from those which
they originally possessed ; and have the power>
in consequence, of exciting on the optic organs
of animated beings, the sensations of illumination
in general, and of color in particular. The
phenomena which these colors display, have
been particularly examined by Sir ISAAC NEW*
TON, and are amply detailed in his celebrated
Lectiones Opticce, as wr ell as by a variety of
others ; and are the objects which the science
of optics is intended to unfold. The theory of
colors, which he entertained, was founded on
the assumption, that the sun was a globe of
fire, emitting rays composed of seven different
colors, which were separable from each other
by means of the prism ; that these seven colored
rays* instead of being compounded, were
original and simple ; and that they constituted
the sources whence the infinite variety of colors
which exist throughout the whole system of
nature, are produced. It was his opinion also,
that all bodies have the property of absorbing
COLOR1FICATION IN GENERAL. 32?
the solar rays, although many bodies have not
the power of emitting them alike ; that is to
say, all bodies do not absorb, or reflect, all the
rays indiscriminately ; some bodies absorb one
colored ray, other bodies another, while they
reflect the rest; and that to the difference
of capacity in different bodies, of absorbing
particular rays, and of reflecting others, the
variety of colors in different bodies, is supposed
to be owing. A red body, for example,
reflects from its surface the red rays,
and absorbs the rest; a green body reflects
the green rays, and absorbs the rest ;
a white body is supposed to reflect all the rays,
and to absorb none ; and a black body to
absorb all the rays, and to reflect none; or, in
other words, the different colors which different
bodies assume, are supposed to depend on
the want of affinity, which particular bodies
possess for particular rays, by means of which
those rays become reflected from the body on
which they fall; that while no individual ray,
but the whole of the primary colors, reflected
and emitted to our organs of sense, are absolutely
necessary in order to exhibit the color
of WHITE ; so, on the contrary, it is supposed,
that when the whole of the incident
rays are absorbed, and suffocated in the
body on which they fall, they are reflected.
828 COLORIFICATION IN GEKERA5L,
and refracted within it, instead of being reflected
out of it; and that the color of black is thus produced.
Great as the authority may be, from
whence these opinions are derived, they appear to
be contradicted by the different qualities of color,
which every individual substance seems to pos*
sess. If the assertion were true, that the color
of a body altogether depends on the reflection
of particular rays, and the absorption of the
rest , if a body be green, because it reflects the
green rays, but absorbs the rest, if a body
be red, because it reflects the red rays, but absorbs
the rest; it must, evidently, follow from
these assumptions^ that the body which we
suppose to be red or green, is, ipso facto, inherently
and absolutely of every other color,
but red and green.
We must conclude from thence that the body
which we call WHITE, because it reflects all the
rays and absorbs none, is destitute of color altogether;
and, on the contrary, that thebody which
is knownby thename ofBLACK, becauseit absorbs
all the rays and reflects none, is absolutely and
inherently of every color but a black one. Ab*
sorbing all the rays and reflecting none, as the
black body is supposed actually to do, it
is impossible that any knowledge could be
obtained by the eye, of the figure and color
of the body in which all the colors were im*
COtO&IFlCATION IN GENERAL. 329
With respect to vision, a body,
such as this, would be a perfect blank,
invisible to the eye, and only cognisable by
the resistance which it gave to the sense of
touch.
The same consequences would ensue with
respect to what is called WHITE. If a body
appear to be white, because it reflects all the
rays, and absorbs none of them; it is impossible
that any knowledge could ever be obtained
of a white body by the eye ; since, in such a
TOse, it must be destitute of color altogether.
I would, however, ask whether there be any
solid ground for supposing that the different
impressions made on our organs of vision by
the particular rays which flow from particular
bodies, are not equally referable to them all, without
any exception. I would ask whether any
exception ought to be made with respect to jet
‘and to snow? Whether the rays which flow from
both, by which the impressions on our optic
sense excite the sensations of white and black,
havenot an actual existence within those bodies,
or at least on their external surfaces, as much
as on those ofgold or indigo ? Whether the white
wax and the black wick of which my candle is
composed, are not as obvious to the eye, and
as referable to the same cause, as the red flame
that issues from it ? I would ask whether that
hypothesis be built upon a legitimate assurop330
COLORIFICATION IN GENERAL.
tion, which makes the body which is called
black, to arise from the absorbtion of all the
rays, and, at the same time, affirms the substance
which reflects all the rays, and absorbs
none, to be the cause of white; making,
in fact and in truth, black to be white, and white
to be black. Much less is it justifiable to con^
elude that neither black nor white are colors.
Instead of supposing that the infinite variety of
colors and of shades which the whole ofanimated
nature displays, that the black pigment which
gives to the eyes of animals in general, and of
the human species in particular, a character so
marked and striking, and that the beautiful bloom
ofred and of white with which the complexion of
the fairer sex is adorned, wanning the coldest
heart with sentiments of admiration and of delight,
proceed from the existence, within, of
original health and beauty : on the Newtonian
hypothesis, we must, on the contrary, conclude,
that the whole of our perceptions, in these’particulars,
are founded in delusion and deceit:
we are bound to conclude that the most beautiful
complexion of the most beautiful woman,
appears to be what it is not in reality : that the
shades of red and of white mingled together in
such admirable proportions, as they often are,
instead of existing as parts separated from
the blood, and deposited on the skin, from
whence they are conveyed to our eyes by the
tOLORIFlCATlON IN GENERAL. 331
agency of pure and colorless light, never had
an existence on the skin, but that they are
repelled and excluded from it; and that
it is polluted and defaced by the rays alone
which are absorbed within, and not reflected
without, viz. the orange, the yellow, the green,
the violet, the indigo, the purple, the black.
So far, however, from subscribing to these
opinions, however great the authority may be
from whence they are derived, [ feel it my duty
to protest against them, and endeavour to expose
the absurdities to which they lead : they
have, I conceive, been occasioned by an ignorance
of physiology, by not knowing the relation
which exists between the sensitive principle
within, and the substance without, by
which sensation is excited and produced. Instead
of ascribing sensation to the receiver, it
has rather been referred to the thing received,
and impression and sensation have thereby been
confounded together.
Instead of supposing that the pure solar rays
(which in their simple and uncombined state, I
have endeavoured to shew are colorless and invisible)
are colored originally and essentially ;
or, that the infinite variety of colors which AVC
behold, are formed out of the prismatic alone,
I conceive it far more reasonable to conclude,
that the pure solar rays are the carriers and the
agents only ^ that not only the formation, but
332 COLORIFICATION IN GENERAL.
the diversity, of color, principally depends on
the quality of the base with which colorless
light has combined ; that it is owing to this
combination which has taken place between
both, that a new substance (a tertium quid) is
formed, which is colored since it is visible ;
and, which is visible, because it is combined ;
the properties of which are very different in
their combined, from what they were in their
simple elementary state. The matter of light
from being colorless, becomes colored, from
being invisible, it becomes sensible, from being
transparent Only, it participates, in an eminent
degree, in the opacity and quality of the
base, with which it has united ; the result of
which is the production of color. So long.,
therefore, as the eye becomes illuminated by
any object whatever, that object must be considered
to be colored. Illumination constituting
the genus, of which color is the species. In
order, therefore, that vision should exist, it is
necessary that the rays of color which are transmitted
or reflected from different bodies, should
unite, in the eye, in the same order as they
exist in the substances from whence they have
issued, or whence they have been reflected.
The change of color, which different bodies
undergo, by exposure to the solar rays, and
more especially the facility which we possess,
of collecting these colored rays by means of
COLORIFIATION IN GENERAL. 333
proper glasses, and of reflecting them in their
colored state on other bodies, appears to prove,
in a decided manner, that a union has taken
place between the rays of light, and the bodies
on which they have impinged. It is with a
view of preventing this union between them and
the furniture of our apartments, that their introduction
is prevented by blinds and shutters;
and I need not add, that the loss of color, by
exposure to the solar rays, in ribbands which ladies
employ to ornament their dress, is to them
a constant source of lamentation. It is with a
view of preventing the deleterious influence of
light on colored bodies, that various substances
are combined, by painters and dyers, with their
coloring matter, in order to fix the colors, and
to prevent them from flying off. That the loss*
of color, which we behold different bodies undergo
by exposure to the solar rays, proceeds
from their influence, independently of the heat
which subsists in them, is most obvious ;
little or no change of color takes place, although
those bodies are exposed to a temperature
much higher in degree. If colors are not immediately
derived from the solar rays, it may reasonably
be asked, to what sources are they to
be referred? I would answer ; to the infinite
multitude of bodies which exist, not only living
and dead, but common also ; these may be considered
as the radicals or base, by the union of
334 COLORIFICATLON IN GENERAL.
which, with pure, colorless, invisible light/-
colorless and invisible light becomes light, visible
and colored. We behold colored light
evolved, in the most obscure nights, from animals
of the feline race in general, from fish,
from the glow worm, from pyrophori,
from the Bolognian stone, and from different
kinds of crystals and of diamonds. We see
colored light perpetually radiating from bodies
in a state of combustion : the quality of the
color seems altogether to depend on the nature
of the materials of which the base is composed,
subservient to that process ; different kinds of
coal and of peat, always produce a peculiarity
in the color of the flame. The same variety in
the color of the flame subsists in our lamps and
candles, whether they are made of oil, of tallowy
or of wax ; and it may also be observed,
that by some experiments that were made on the
tallow ofan old woman, who had been condemned
to suffer death as a malefactress, it was found
that the candles which were made from it, gave
out a flame of a beautiful blue color. Spirit of
wine imparts a blue, the green calx of copper,
a green, and the white calx of zinc, a flame
as white and as bright as it is possible to conceive
; while, on the contrary, the smoke or
black flame which issues out of many furnaces,
is often as black as jet. This combined light
is often proved to exist in the atmosphere, by
COLORIFICATION IN GENERAL. 335
the different colors, which different bodies situated
in it, are found to display, by the clouds,
so diversified in appearance, by the electric
fire, as well as by different parts of the planetary
system. Who is there, that has not observed
the flery color of the rising and the setting sun,
and the pale and colorless appearance which it
assumes in the middle of a clear day? How is it
possible, with all these facts constantly before our
eyes, not to admit, that it is owing to the union
which has taken place between the solar rays
and the matter of the medium through which
they pass, that these colors are produced. No
proof, perhaps, is more strong, of the uniformity
existing in the composition of the atmospheric
matter, by which the medium above is
filled, than the uniformity in the rays of color
which are formed by the passage of the rays of
light through it, and which are separated from
each other by means of the prism, and thence
called prismatic colors. It is for the purpose of
describing the different mechanical phenomena
which these different colors display, that the
science of optics is especially designed, the leading
propositions of which are as follows.
Def. 1. Light. (Color it ought to have been
called.) Light is that, which proceeding from
any body to the eye, produces the perception
of seeing. 2. A ray of color is an exceedingly
small portion of light (or matter) as it comes
336 COLORIFICAT10N IN GENERAL,
from a luminous body. 3. A body which is*
transparent, or affords a passage for the rays of
light, is called a medium. 4. Rays of color,
which coming from a point, continually separate
as they proceed, are called diverging rays.
- Rays which tend to a common point, are”
called converging rays. The divergency or
couvergency of rays, is measured by the angle
contained between the lines, which the rays
describe. 6. Rays are parallel, when the lines
which they describe, are parallel. 7. A beam
of color, is a body of parallel rays : a pencil of
rays, is a body of diverging or converging rays.
8, The point from which diverging rays pro-*
ceed, is called the radiant point ; that to which
converging rays are directed, is called thefocus.
- A ray bent from a straight course in the
same medium, is said to be inflected.
Laws of refraction, or the rules which different
rays of color obey, when they pass through
different media.
- A ray of light, bent from a straight course,
by passing out of one medium into another, is
said to be refracted.
- The angle of incidence, is that which is
contained between the lines described by the
incident ray, and a line perpendicular to the
surface on which the ray strikes, raised from
the point of incidence.
- The angle of refraction, is that which is
COLORIFICATION IN GENERAL. 337
contained between the line described by the
refracted ray, and a line perpendicular to the
refracting surface, at the point in which the
ray passes through that surface.
- The angle of deviation, is that which is
contained between the line of direction of an
incident ray, and the direction of the same ray
after it is refracted.
Def. 1. A ray, turned back into the same
medium, in which it moved before its return, is
said to be reflected.- 2. The angle of reflection,
is that which is contained between the line
described by a reflected ray, and a, line perpen-,
dicular to the reflecting surface at the point of
reflection. 3. The angle of reflection is equal
to the angle of incidence.* Vid. Enfleld.
* A Latin translation of the Optics of Ptolemy, a work
which was supposed to be entirely lost, as we only possessed
a few lines of it, which have been transmitted by Bacon, has
lately been discovered by Count LAPLACE, in the imperial
library at Paris. The translation is by Ammiratus Eugenius
Siculus. The first book is wanting, as it was wanting in the
original Arabic, from which Ammiratus made his translation.
From this work, it appears that Ptolemy was well acquainted
with the effects and laws of refraction, and that, in this respect,
he was even more advanced than Tycho, Kepler, Hevelius,
and all the astronomers till the time of Cassini, who was
the first among the moderns that asserted that refraction did
not entirely cease up to the zenith. But what is still more
curious, and was never in any manner suspected, is that Pto-
Z
338 COLORfFICATION IN GENERAL.
The motions, which the different colorific
rays describe, in passing through different media,
are so regular and uniform, that these
motions are reducible to mathematical principles,
and can be illustrated and proved by mathematical
rules. Of the utmost importance,
it must, nevertheless, be confessed, is the distinction
which exists between the illustration of
those phenomena, by mathematical rules, and
the causes by which those phenomena are produced.
Each of these objects has its own
principles, and he who confounds the one with
the other, involves himself in error and in confusion.
To the mathematician, the office be^
longs of ascertaining the quantity of matter
which the different rays contain, and the extent
of space which they fill, the velocity they
describe, and the degree of mechanical effect (if
any) which they produce on other bodies. To
the chemist, the province belongs, of exploring
the quality of the material? of which different
colors are composed, and the best means by
which they may be factitiously prepared. To
the physiologist and metaphysician, are the
higher duties allotted, of ascertaining the rela-
Jemy was also as well acquainted as we are with the refraction
which light undergoes, in passing from air into water or into
glass, and that he has given tables of it for every ten degrees
of the angle of incidence.
C0LORIFICATION IN GENERAL.
tion which subsists between impression ?tnd
sensation, between the substance without,, &n$
the sensitive principle within, between the
primary and secondary qualities of matter
Without a previous knowledge of these subr
jects, optics, or the laws of vision, can never
be scientifically understood ; or the nature anc|
cause of cojor be ascertained.
If sensibility be separated from animation,
and animation from matter, all the secondary
properties of matter, are at once obliterated
?
and lost ; solids are bereaved of their figure,
liquids of their flavor, gases of their sound, and
light of its colors. Except the attribute of ex–
tension, which is common to the whole, nothing
is left to solids but their resistance, to liquids
but their mobility, to gases but their expansibility,
and to solar rays, nothing but their,
motion. Ignorant of these truths, the generality
of chemists haje confounded the sensation
with the impression, and mistaken the one for
the other, not only with respect to the different
secondary qualities which I have described, but
more especially to those by which the sedations
of heat and of cold, are excited, and which I
shall designate by the generic name of TEMPS.-.
HATXJRE.
CHAPTER XVII,
ON THE MATTER OF TEMPERATURE IN GENERAL,
AND OF REFRIGERATION IN PARTICULAR.
IT is to be lamented that the English have conceded
to the French chemists, the term by which
that matter is designated and known, which
has the power of exciting the sensation of heat
or warmth to animated beings in general, and
of expanding common matter in particular ; and
both, I conceive, are blameable for having
changed the word fire, feu, for that of caloric.
Feu, like fire, is the abstract word, expressive
of the abstract thing ; whereas the word caloric*
by conveying with it the idea of chaleur, which
in English means heat or warmth, would rather
seem to confound together the sensation which
is felt, with the substance by which the sensation
is excited, as if both subsisted in one and
the same subject. The Romans preserved the
distinction between both ; between ignis or fire.
REFRIGERATION. 341
the thing signified, and calor, or the sensation
of heat which was produced in consequence of
the impression. The same observations equally
apply to the different bodies by which the
sensation of cold is excited.
Such is the mutable nature of the organs of
sense, whidi animated beings in general possess,
that the sensations either of heat or of cold
which they feel, must ever be considered a test,
the most uncertain of the different degrees of
temperature existing in different bodies ; the
same quantity of matter of temperature, applied
to the organs of sense, not only produces
different sensations to different individuals, but
to the same individual at different times. If a
man plunge his hand into a basin of water, at
the temperature of 50 of the present standard,
and remove it into water of the temperature of
100*, the former will feel cold, the other hot; and
ifhe remove the one of 50 to one of 33, the one of
50, which felt cold at first, will feel hot, when
compared to what it was when situated in that
of the temperature of 100. The most certain
means we possess of ascertaining the different
quantities of the matter of temperature existing
within a given bulk, consist in the different degree
of dilatation and of contraction, occasioned
to bodies exposed to the influence of that temperature,
under the different states of refrigeration
and of combustion, as they may be called.
$42 REFRIGERATION.
instead of examining the various causes, iby
the operation of which different substances ac^
quire different properties; in consequence of
new ‘combinations wlich take place between
them ; how aether is volatilised into vapor, and
ivater consolidated into ice and snow, by means
of which these bodies have the wower of exciti.
ing the sensation of cold in animated beings in
general : chemists have come to the unanimous
-resolution of considering cold as a non-entity;
dependent altogether on the privation of fire, or
caloric. I would, however, put it to the feeU
ings of these gentlemen, whether snow or ice*
applied to bodies in which those sensations are
produced, have not an actual existence, as much
as those which proceed from a flame of fire by
which the sensation of heat is excited : not by
the abstraction alone of fire or caloric from the
body, but by the palpable application of ice to
- I would ask, whether the effects which are
produced during the winter in the polar regions
as well as in other countries, where we behold
liquids converted into a solid form, water become
ice, vegetation suspended, animation
rendered torpid, and both by mortification
decomposed and destroyed : I would ask, whether
it be not reasonable to conclude^ that these
effects have been produced by the new modification
of matter that has taken place: and whether
it must not appear somewhat strange to men of
REFRIGERATION. 343
‘Common feelings, who possess common sense,
to be told, by the most enlightened chemists
and experimental philosophers, as they
call themselves, that none but ignorant
fools, if any there are so foolish, dare to
think so.*
So long ago as the year 1684, was found in
the essays of 1’Academie del Cimento, a paper
which has been translated, to shew the nature
and properties of cold ; and the recent experiments
lately made by Mon. PJCTET decidedly
prove, that what is called cold, may as easily
be reflected from snow and ice, as what is called
heat, from aflame of fire. Pictet placed two
concave mirrors, made of tin, at the distance of
ten feet and a half from each other ; a very delicate
thermometer was put into the focus of
one, and a glass mattrass, full of snow, into the
focus of the other ; the mercury in the thermometer
immediately sunk several degrees ; and
when the mattrass was removed, which contained
the snow, when the rays of snow ceased to
* I must refer the reader to the chapter on Sensation. I
hope that he is, by this time, sufficiently acquainted with the
difference which exists between impression and sensation, not
to know, in speaking of ice being cold, and of fire being
hot, that these bodies are not cold or hot essentially or per se,
but only cause impressions which excite the sensations of cold
and of heat.
344 REFRIGERATION.
be reflected upon the thermometer, the mercury
rose to the temperature of the surrounding medium.
The degree of cold, in another experiment,
was increased, by pouring upon the snow
some nitric acid; the consequence of which
was, that the mercury in the thermometer,
which was exposed to the focal point, sunk six
degrees lower than before.
Mr. WALKER, who spent much time in prosecuting
experiments, with a view of ascertaining
the greatest quantity of cold, that could be
Artificially produced, found, that by mixing two
parts of concentrated nitrous acid, by weight,
and one part of water, and by adding to this
mixture, when cooled to the temperature of the
atmosphere, of Glauber salt* Ibiss. and of
sal ammoniac, Ibiss. I say, that on adding the
Glauber salt to the nitrous acid, the thermometer
fell 52 degrees ; that is, from 50, which it
was at before, down to 1 ; and on adding the
sal ammoniac, it sunk to 9 belowr 0. By these
means, Mr. Walker was enabled to freeze
quicksilver, at the time when the mercury was
at 45. in the air.
The union of sulphuric acid, ofspirit ofwine,
and various other substances, with snow, will
produce a low temperature to an intense degree*
and by a proper management of artificial means,
ice may be formed for the luxury of man, in
REFRIGERATION. 345
those countries in which the temperature of the
climate is generally very high.*
Although the temperature of the air varies in
different countries, as well as in the same country
at different seasons, it may, nevertheless, be
considered a general truth, that when the temperature
is increased on the plain surface, the
minimum of low temperature prevails at the
polar regions, and progressively becomes higher
towards the line of the equator, when it may
be said to have attained its maximum. The
temperature of Siberia and of Africa are as
different as they are distant from each other;
in the one, it is found, according to the present
scale, as low as 5 of Fahr. t in the other, as
high as 114 degrees: although this great difference
of temperature exists on the plain surface,
a greater uniformity prevails, in the upper parts
of the firmament, insomuch that in ascending
the highest mountains of the world, at whose
* At Benares, in the East Indies, the manufacture of ice is
carried on to a very large scale; a piece of ground is divided
into plots four or live feet wide, the borders of which are
raised four inches above the central surface: dry straw is
placed on this part, and a number of earthen pans, of a very
porous quality, smeared over with butter on the inside, are
placed on it. In the evening, water is poured into these pans,
and ice from one to two inches in thickness, is found in them,
the ensuing morning.”
346 REFRIGERATION.
base the temperature \vas intensely high, their
temperature at which point is found gradually
to sink towards the summit, the whole of
those mountains are constantly coated and
covered with ice and snow.* The actual exexistence
of ice and of snow, in those regions,
decidedly proves that the solar rays are not
ignious rays, and that the sun is not, as Sir I.
Newton supposed it to be, a globe of fire. The
effects which ice and snow produce on other
bodies, are as definite and positive, as those
which are produced by fire ; the power of fire
to produce the sensation of warmth is not more
manifest, than of ice to excite the sensation of
cold; the one of expanding bodies, the other of
contracting them.
Instead of ice subsisting as the negative of
jfire, or cold the negative of heat, I consider that
the former is as positive as the latter, as
positive and separate, as the attributes of those
bodies which excite the sensations of sweetness
and of bitterness of odor and of sound.
I shall not stop, at present, to examine the
means by which the process of refrigeration is
accelerated and retarded^ or to investigate the
nature of those causes, by the operation of
which it is accomplished, by which the liquid
and aqueous particles, after being converted
from a liquid to ‘a gaseous form, and raised from
* Vide page 153.
REFRIGERATION. 347
the plain surface to the highest points of elevation
in the firmament, are afterwards resolved
to a liquid state, and ultimately made to
assume the consolidated form of ice and of
snow ; the effects of which, on the whole face
of creation, are known to the most superficial
observer. I shall, proceed, in the next chapter,
to explore the nature and cause of fire,
of that matter distinguished from every other
species by the sensation of heat which it excites,
in animated beings in general, and by the
expansion which it causes to common matter
in particular.
CHAPTER XVIIL
ON CALORIFICATION.
SECTION I.
On the Source from whence Fire is derived, and
the Means by which it is generated.
THE free and ready admission of the solar
rays in bodies, both diaphonous and opaque,
will be readily understood, after the description
which I have given of the subtlety of their
nature, and the power of motion which they
inherently possess. While they subsist in their
pure and elementary state, there is every rea*
son to believe, that they neither excite in animated
beings the sensation of illumination in
general, nor of heat or cold in particular ;
they are, in fact, destitute of all the attributes,
by which the identity of color or of
temperature is characterised : they produce,
on the common matter into which they may
have been admitted, none of the phenomena of
ignition or of cumbustion ; they subsist in those
bodies, in what may be called a latent and elementary
state, and are altogether invisible and
CALORIFICATION. 349
insensible. While the solar rays subsist in this
pure and elementary condition, they are as
different from what they are in a state of combination,
as the attributes of different compounds
are different from the elementary parts
out of which they were formed, as different as
the neutral salt is different from the acid and
the alkali, as ice is different from water, as
color from light, and as figure itself from extension
simply: insomuch, – that the definition
that would apply to the accident, would be altogether
irrelevant and improper for the element.
It is in manifest contradiction of this
truth, that the doctrine of latent heat, as
invented by Dr. BLACK, and as it is handed
down to us at this day is founded. According
to this hypothesis, fire, or the matter of
heat, as it is called, is supposed capable of
existing in two separate states ; in the one, it
excites the sensation of heat to animated beings
in general, and causes expansion to take place
in common matter in particular. In the othef
state, it neither excites sensation nor produces
expansion; in the former, it subsists simple
and elementary, in the latter, it is united and
neutralised (as it were) with th bodies in
which it is involved ; insomuch, that whenever
combustion, or the evolution of fire, takes
place, it is supposed to arise from the decomposition
which pure fire has undergone, that
CALORIFICATION.
being loosened from its confinement, it then
produces the various phenomena of sensation
and of illumination, of expansion and of combustion.
The former state is known by the
appellation of sensible heat, the latter of latent
heat. If the doctrine, however, of latent fire
were admitted (the term latent heat, as it mistakes
the sensation for the body which excites
it, appears to me a most objectionable one,)
we should be driven to the absurdity of having
two different definitions for one and the same
substance. A definition of fire in a sensible,
and another in a latent state : we should in the
one, define fire to be a substance which excites
the sensation of heat or warmth in animated beings
in general, and produces expansion in common
matter in particular ; in the other, ih&tjire
is a substance which neither excites sensation nor
expansion. This is both contradictory and absurd.
I shall, therefore, proceed to examine
the sources from whence fire, caloric, or sensible
heat is derived, and the means by which
it is produced.
If we search for the sources from whence fire
is derived, it will appear that it does not form
any part ‘of the essential attributes belonging
either to the resistance of solid, or the mobility
of liquid matter: neither are there any
grounds for supposing that the different rays of
light, which flow from the different parts of the
CALORIFICATION. 351
planetary system, are ignious or calorific rays.
The lunar rays have been collected and condensed
through different spectra ; although the
illumination, in consequence produced, was
more splendid and brilliant than the brightest
flame of the best candle, no sensible increase
of temperature was occasioned from them ; the
intense degree of cold, indeed, which frequently
prevails during the winter season, in different
countries, although illuminated by the rays of
the moon, decidedly prove that those rays are
not essentially hot. The observations which
have been made with respect to them, during
the winter season, more especially apply to the
solar rays at all seasons. Such is the extreme
state of refrigeration which every substance un^
dergoes, when it is exposed to their influence,
at the highest points of elevation, that the most
common observer will be led to conclude, that
the solar rays are not calorific rays, nor the sun
itselfa globe offire. It is very true, that the solar
rays have been examined by Dr. HERSCHELL,
and by other philosophers ; these experiments
satisfactorily prove, that the different colorific
rays have different degrees of temperature;
they, however, prove nothing with respect to
the temperature of pure light ; the colorific rays
which were separated from the colorless,
manifested all the phenomena of color and
temperature; the colorless, on the contrary.
352 CALORIFICATION.
were altogether insensible and invisible, while
they subsisted in their elementary and individual
state ;. it was not until they had united
with the muriate of silver, that it turned to a
black color, and temperature was produced.
While the attributes of pure light, therefor^,
enable us to understand its actual existence, in
different bodies, without either exciting sensation
or expansion, they lead to an explanation of the
various changes which different bodies are found
to undergo, in consequence of their union and
combination with it, by means of which the
various phenomena of color and temperature
are produced.
All the facts which we possess, go to prove,
that the solar rays not only remain in different
bodies in a latent state ; but that they pass
through particular bodies without uniting with
them ; they pass through snow, without melting
it, they pass through glass, without any
sensible increase of temperature. It may, indeed,
be observed in a general way, that the
solar rays pass through transparent bodies,
without being either arrested by them, or uniting
with them in any great degree. It, on. the
contrary, appears that the color of a body has
a considerable influence on them; insomuch,
that if bodies of different -colors, placed contir
guous to each other, are exposed to the solar
rays, the different changes which take place on
CALORIFICATION. 353
the temperature of each are obvious and direct.
This fact was proved and established by a long
series of experiments, first began by Dr. Hook,,
continued and varied by Drs. Franklin and
Priestley, by Mr. Cavallo, Mr. Davy, Dr.
Herschell, Sir Harry Inglefield, cum multis
aliis.
- Dr. FRANKLIN placed upon pure snow,
pieces of cloth of different colors, viz. white,
red, blue, and black, and exposed them to the
solar rays : he found that the pieces of cloth
sunk in the snow with different degrees of rapidity,
in proportion to the darkness or light*
ness in the color of the cloth; and that this
sinking of the cloth in the snow was caused
by the heat produced upon the cloth, and
thence imparted to the snow, which melted
in consequence.
- Mr. CAVALLO painted the bulbs of different
thermometers, not only with the different pris-*
matic colors, but black and white also, and
exposed them all, with respect to the rays of
the sun, in the same relative situations * he invariably
found, that the mercury in the thermometer,
whose bulb was either unpainted,
or painted white> was lower than in any of
the others* the mercury rising, in a regular
and progressive ratio, from these to the one
which was painted black, which was the highest
of the whole.
A A
354 CALORIFICATION.
- Mr. Davy varied Mr. Cavallo’s experiments
; the result, however, was found to be
uniformly the same. He took six pieces of
copper, of equal dimensions, the upper surfaces
of which he painted white yellow red
green blue and black : the opposite, or
dark side, he smeared over with lard, or cerate,
which he previously ascertained to melt when
heated to the degree of 76* of Fahr.: he placed
them in such a manner, as that the painted surface
only.was exposed to the rays of the sun
he invariably found, that the cerate attached to
the white bulb, was the longest time in melting,
and that the rapidity of the liquifaction
gradually increased, from the yellow to the
red, from the red to the green, from the green
to the blue and black.
Dr. HERSCHELL made experiments of a similar
nature, with the same result ; he was led
to perform them, in consequence of the necessity
he was under, at the time he was making
observations on the sun, by means of telescopes,
of making use of colored glasses, to prevent
the ardor of the rays from injuring his
eyes. He found, that when the glasses were
of a color, so deep, or dark, as to interrupt
the light, they very soon cracked and broke
in pieces. This circumstance induced him to
examine the heating power of the different colored
rays ; for which purpose, he made each of
CALORIFICATION, 355
them, in its turn, fall upon the bulb of a thermometer,
near which two others were placed to
serve as standards : the number of degrees,
which a thermometer, exposed to the colored
ray, rose above the other two, indicated the
heating power of that ray, he found that the
thermometer, which was either naked, or
whitened with paint, was lower than the one
which was blackened and that the white
thermometer, wrhen exposed to the red ray,
rose from 55 to 58-3 degrees* The black thermometer,
exposed to the same ray, rose from
58 to 61. The same thermometer, exposed to
the dark ray, rose in a greater proportion;
while the former scarcely rose one half degree,
the latter rose from 59 to 64. It is not surprising
that Dr. Herschell should express his
astonishment at finding that the illuminating
and heating power of the rays, follow such different
laws. According to the present doctrine
of fire, this difference is altogether inexplicable;
but according to the principles which
I have endeavoured to develope, they are the
effect naturally flowing from cause. We
find the colored, and, consequently, the combined
rays of the sun produce heat ; they produce
heat because they are combined, and they
are combined, because they are found to excite
the sensation of heat. The degree of heat these
rays are found to excite, will always depend on
AA 2
356 CALORIFICATION.
the intimacy of the combination, and the nature
of the color will arise out of the peculiarity iu
the arrangement of the particles of the matter
with which the union is effected. The purest
rays, therefore, which subsist in a most elementary
and nilcombined state, as we have seen
before, are destitute of fire, and of color.
When the solar rays pass through water
which is pure, or that which is colored, the
same difference in the temperature takes place.
At a time when the mercury of a thermometer
was at 61 in the air ; two other thermometers
were plunged into the clear, and into the colored
fluids ; while the former in fifteen minutes
only, rose to 64, the latter got up to 76.
If the quality of the base, on which the solar
rays fall, produces such a difference in the
degree of temperature, is it not, I would ask,
legitimate to conclude, that the cause of the
temperature itself which is produced, is the
result of the chemical union, which has taken
place between the one and the other ; that as
chemical affinity, or elective attraction, altogether
depends on the contrariety which exists
in the nature of the different parts, out of which
compounds are formed, so the intensity of the
temperature which is generated, will depend
on the contrariety which exists between the
purity of the solar rays, and the quality of the
base, with which they have combined.
CALORIFICATION. 357
The truth of this conclusion, is rendered
more apparent, when we reflect on the means
by which fire is factitiously and spontaneously
produced, while the union which takes place
between the solar rays and water is the causes
of which gasification is the effect, the union
of the solar rays with opake matter, on the
contrary, is the cause of combustion. When
the solar rays are brought to a focal point in
pure water, they produce in it, a slight increase
in its temperature ; if a piece of wood,
however, be immersed in it, the difference is
obvious and striking; under circumstances
such as these, the wood has been actually
burnt and charred, and a great increase in the
temperature of the water produced. Although
the concentration of a lens, enables us to collect,
and to condense, an immense mass of rays, to
one point, so as to have the whole accumulation
within a very small compass; if that
point be in the air, no sensible effect is
produced; if, on the contrary, a solid substance
be (exposed to its influence, fire the most
vivid and intense is the direct and immediate
consequence, and all the phenomena of ignition
and of combustion immediately follow.
As the materials of which fire is composed,
are all referable to light and opake
matter, so the means by which it is produced,
are either chemical or mechanical, separately,
358 CALORIFICATION.
or in conjunction. That this is the fact, will
appear, if the effects are examined, which are
produced by compression alone, in consequence
of mechanical power. If a volume of
air, enclosed in a syringe, be condensed, from a
large to a small compass, the generation of fire
is so great, as to be immediately rendered sensible,
by the increase of temperature, which is
felt through the sides of the syringe. The
power of friction, and of percussion, between
solid bodies, in the generation of fire, is familiar
to all ; by means such as these, a spark of
fire, and of color, may be evolved by the friction
together of two pieces of quartz, two
sticks may be ignited to a flame, a nail be
hammered redhot ; and the electric fire itself
can be excited near the surface of the earth, by
means of an electrical machine, as perfectly as
we often behold it produced in the upper regions
of the air. The consequences of this are
manifested by the fire, and .color, which are
generated and evolved. Although the electric
may form a distinct species from our common
culinary fire, it belongs to one and the same
genus, in its nature, and in its essence.
Like other species of fire, it produces co-
Jor, and excites heat, it dilates bodies,
it fuses metals, it kindles combustibles, as
they are called, and is most ardent in dry
CALORIFICATION. 359
weather. The means by which the electric
fire is generated on a machine, are evidently to
he referred to a mechanical cause ; by the
light, which is latent, in the atmosphere,
being forced by the motion and pressure of
the cylinder, to unite with the opake matter,
in the form of an amalgam.
From the mobility which exists in the particles
of which liquid and gaseous bodies, in
general, are composed, a more extended surface
between each presents itself; so that
wherever ignition takes place in them it not
only extends more widely, but is accomplished
more rapidly than in bodies of a more compact
nature ; instead of slow combustion, explosion
ensues.
The generation of fire takes place by the
chemical combination together of hydrogen
and oxygen gas ; hydrogen gas is perpetually
given out during the decomposition of
animal matter, and when there takes place a
chemical union of that gas with the oxygen
gas which the atmosphere contains, explosion
immediately ensues, manifesting the phenomena
of color, and of temperature, the
elastic power which these gases separately
possessed by combination become weakened
and lost ; insomuch, that the water which was
either suspended in them, or chemically com360
CALORIFICATION.
bined with them becomes deposited from them,
in the form of rain. The whole of this phenomenon,
is exactly similar to what takes place in
the upper regions of the air, by the effect of
lightning*
*
It has been owing to this ultimate effect, that chemists
have been led to conclude, that these airs are the elements
out of which water is constituted and formed ;^-that they
bear, in fact, the same relation to water, as cause does to
effect, that a whole does to a part. If this conclusion were
as true as it is false, if water were the effect produced, and
air the cause producing ; the consequence would be, that the
matter of the producing cause, (i. e. air,) must be sufficient in
bulk and quantity, to account for the whole quantity of the
effect produced, (i. e. the water.) I would then ask, whether
it is not prima facie, a violation of common sense to suppose,
that all the water which is kept suspended in the air, in the
form of atmosphere and clouds, all the water which flows in
rivers and lakes, and which exists to an unfathomable depth
in the ocean, can be the product of these airs. It might as
reasonably be supposed, that all the water in the ocean is
formed out of the rivulets and brooks, instead of the waters
of these being parts of which the ocean is the whole. That
the quantity of air is altogether insufficient to acconnt for all
the water which actually exists, is further proved by comparing
the relative densities of each, as ascertained by the
relative degrees of gravity in each. The relative gravity of
water to oxygen gas, is as 1 to 1,000; of water to hydrogen,
as 1 to 13,000 ; so that 1,000 cubic inches of the former, and
13,000 of the latter, by combination, produce one ounce of
water only ; not the superior density of the one, and the rarity
of the other, must be taken to the account, but the
extent and limitations of each also : although we cannot faCALORIFICATION.
361
If we examine the changes which those elements
have undergone, of which this new compound
is formed, their sensible properties will
be found totally different in their combined,
from what they were in their elementary state.
While therays of light proceed from theirsource
to boundless space, with the velocity of 200,000
miles in one second of time, the motion of the
calorific rays are limited and retarded, and
ultimately arrested, while the direction of the
motion of the one is from the perpendicular to
the base ; the motion of the other is rather directed
from the base to the perpendicular,*
thorn the depth, or calculate the quantity of water which
exists, we know, with tolerable accuracy, the limited extent of
the region of the air. We may, therefore, conclude, that the
one is totally unequal to account for the existence of the other.
That these airs did not exist originally, or antecedently, to
water, is proved from hence, that either one, or both of them,
are the produce of vegetable or animal action ; or from the
decomposition which living beings undergo, by the process of
putrefaction and decay. I do not mean to speak of the factitious
means by which they are prepared. I allude to the
common sources from whence they are actually and spontaneously
obtained. If these airs have their source from living
beings, if they are effects of which living matter is the cause,
it is impossible that they can be the sonree and the cause of
water, because water existed antecedently to cither the one,
or the other.
* If two bars of iron, of equal dimensions, are placed
through the same fire, the further extremity of the upper one,
302 CALORIFICATION.
The light loses its transparency, and becomes
thickened, from being colorless it becomes
variegated, from being destitute of
temperature, it acquires it to an extreme degree,
instead of permeating transparent and
diaphanous bodies, and remaining in them
latent and unaltered ; the matter of fire, on
the contrary, manifests its actuality and presence,
by the production of temperature like
streams of blood, that circulate through the
most minute vessels of a living system, it perwill
become redhot, much sooner than the further extremity
of the lower one. So little is the tendency downwards in the
motion of fire, that COUNT RUMFORD, was enabled to make
the upper surface of water to boil, at a time that a cake of ice,
which he had placed at the bottom of the vessel, remained
unaltered and frozen ; and the increased degrees of temperature,
at the top of a temple, and of a theatre, from what
exists at the bottom of it, must have been observed by all.
While fire, or the matter of heat, increases the bulk, it decreases
the weight of bodies, making them lighter than
before, although it is more opake, than the element of light,
it is, perhaps, the rarest and most subtile compound which
exists. If its density could be measured in the element of
light alone, it would gravitate and fall ; but being more elastic
than the atmospheric medium in which it is situated, it
overcomes the resistance of the air, and rises through it. It
is the case with smoke, in which a large proportion of fire is
involved ; it is found to rise faster in a dense, than in a rare
atmosphere ; and it sinks altogether in a rarified one. The
effect is rendered very visible under a receiver, in which any
substance may have been burnt the smoke ascends at first
CALORIFICATION. 363
meates and penetrates the pores of which the
most solid substance is composed, expanding
and devellating the whole into parts, and like
the baseless fabric of a vision leaves not a
wreck behind. It is, I may say, owing to the
warfare of opposite elements, uniting and fighting
together, that the different materials of
which fire is constituted, lose the identity,
which each separately possessed. So far,
therefore, from lire being a simple, elementary
body, it is far more reasonable to suppose, that
it is one which is compounded and factitious
and that it bears the same relation to light and
opakc matter, as the prismatic colors to atmosphere
and light ; the opake matter, becoming
the pabulum to light; and light the pabulum
to opake matter, the result of which is the
generation of fire ; fire, therefore, neither inheres
in any part of the materials of which the
world is composed ; nor in the pure solar
rays, the immediate and proximate cause, appears
to consist in the chemical union and comfrom
the bottom to the top ; when the air, however, which the receiver
contains, becomes exhausted, the column ofsmoke is suspended,
and as it becomes heavier than the medium which it has
displaced, (at the same time that it has lost its elastic power,
from the fire which it contained,) it becomes heavy and sinks
to the bottom. Fire may, therefore, be considered heavy
with relation to the matter of light, but light with relation to
all other bodies.
364 CALORIFICATION.
bination, which has been accomplished between
both. Combustion is, in fact, an act of
solution, by the agency of which, the bonds
which hold together bodies the most compact,
are loosened and separated, by which they are
changed from H solid to a liquid state, and
finally dissipated in vapor.*
* LAVOISIER’S opinion of combustion is, that air contains
a quantity of the matter of tire, chemically combined with it;
that during combustion, the gravitating matter of air, combines
with the combustible body, and parts with its fire,
which appears as heat and light. He considers free caloric,
to be the portion which produces temperature ; and that
combined caloric, is that portion which is chemically combined
with the body, and cannot be abstracted from it by
chemical decomposition, and which is disengaged during combustion,
owing to the combustible body exerting a stronger
attraction for it, than the caloric does to the concrete oxygen.
He supposes, therefore, a combustible body to be one, which
has the property of decomposing oxygen gas, one for which
the oxygen has a stronger affinity, than it has to the matter of
heat; so that combustion is nothing more, according to
him, than the separation of oxygen from the matter of heat.
He is also of opinion, that air is compounded of the matter of
fire, With a substance which is its base ; when a substance
with which it has a greater affinity, is presented to this base,
the matter of fire becomes free, resumes its properties, and
appears with heat, flame, and light.
CALORIFICATION. 365
SECTION II.
(f,
*
%Poyr of Fire over Liquids and Gases.
Such is the power which fire absolutely possesses
over different bodies, whether they be
solid or liquid, that we know of very few, that
are capable of resisting its action, when it is
accumulated to an extreme degree. By exposure
to a certain degree of fire, it is probable
that most solids maybe converted into liquids;
and all liquids, by increasing the quantity of
fire, may be made to undergo the further
change from a fluid to a vaporific state. The
dilatation, which different bodies sustain by
the agency of fire, varies in a considerable degree
; neither does the degree of expansion
bear any certain proportion to the quantity of
fire which is introduced. Solids, for the most
part, have a greater power to resist its influence
than liquids, and liquids more than gases;
although the volume of water is somewhat
augmented, as its temperature increases from
the free2ing to the boiling point, the augmentation,
however^Js small, when compared to
what it has attained in its vaporific state*
If the properties of this vapor (of this new
366 CALORIFICATION.
compound) be examined, they will be found
to be totally different, from those of its
elementary parts ; instead of the fire radiating*
from a point, to an indefinite extent, its power
of motion becomes more limited and bounded,
in consequence of the resistance to which it is
exposed : and, instead of the water continuing
1
incompressible as before, it acquires an expansible
power, to a very great extent. At the
point of ebullition, the dilatation which it then
undergoes, suddenly increases in a greater degree,
than the augmentation of the fire could
be supposed capable of producing. Mr. GREGORY
very properly observes, that there is a
very considerable difference in the result of experiments,
performed with a view of determining
the ratio, between the densities of water,
and the vapor of water at the boiling point ;
while Mr. HENRY states it to be as 1728 to 1 ;
others have carried it as far as 2, and even 3,000
times its original bulk. However varied the proportion
may be, the fact is universally admitted,
the power which vapor possesses of pressing
upon surrounding bodies, and of overcoming
their resistance, is familiar to every one. The
celebrated Engineer, VAUBAN, has observed,
that while 140lbs. of gunpowder, can only explode
and overcome the resistance of 30,000
weight; 140 Ibs. of water, converted into vaCALORIFICATION.
367
por, will explode and blow up, a weight of
77,000 Ibs.*
Great as is the power which vapor possesses,
it is evidently to be referred to the agency of
the fire which it contains ; the water which
enters into its constitution, is of itself as incapable
of expanding, as it is of condensing ; no
force, however great, (as I have before had
occasion to notice) has been able to diminish
its volume : it, in fafct, is incompressible, and,
therefore, can suffer no compression ; when
water, therefore, is acted upon by light, or by fire,
and converted from a liquid to a gaseous, or vaporific
state, the substraction of the agent in the
process of evaporation, is always accompanied
by a loss of the attribute, which the water had
acquired, the vapor returns back from dryness
to moisture, from an elastic and expansible, to
an incompressible and an inelastic condition. Although
both vapor and gas belong to the same genus,
they form very different species. The conversion
ofwater into steam, by the agency of fire,
is of a very transient nature; whenever the matter
of heat is abstracted out of it, the water
returns from its vaporific, to its liquid state ;
whereas the gasification of water, by the agency
* No wonder then, that the ingenuity of man, should have
converted a power such as this, to the most useful purpose,
as is found in the steam engine.
368 CALORIFICATSON.
of the solar rays, not only preserves its gaseous
form, near the surface of the earth, but at the
highest point of elevation, and at all degrees of
temperature, whether high or low. It is this property
which particularly distinguishes gas from
vapor ; vapor by the reduction of temperature,
loses all the properties which it had obtained,
and returns to its liquid state; gas, on the
contrary, not only preserves its gaseous state
at all degrees of temperature, but of external
pressure also; while a cold decanter, introduced
into a hot room, will separate the water
from the gas/and collect it on its whole surface:
gas will not only remain unaltered by time,
but preserve its gaseous form under unequal
degrees of temperature, for an indefinite period.
The difference which exists in the property
of gas and vapor, clearly proves the difference
which exists in the nature of the agent, by
which the conversion of water into vapor, and
gas, had been accomplished : it manifests that
the power of the solar rays far exceeds the power
of caloric, or fire. Although the dilatation be
very considerable, which water undergoes when
it is converting from a liquid to a vaporific
state, it, nevertheless, bears no proportion
%to
its power of dilatation after it is actually
formed into vapor. From Mr. DALTON’S
experiments it appears, that however different
the chemical properties of different gases may
360
be, the expansibility is alike in all, and that
they all undergo, by the addition of the same
quantity of fire, the same relative increase in
their bulk. Mr. Dalton found that 100 parta
of air, by having its temperature raised from
65 to 212, expanded 132-5 parts, which gives aft
increase of bulk of 000,207, or ^ parts to 1.
Can it, I would ask, be supposed that this wonderful
increase of bulk can arise from the in*
creased pressure of the air upon it, and that
the removal of resistance is the cause from
whence this expansive power is derived? A
supposition, such as this, is a most erroneous
one ; the abstraction of any compressing force,
from any expansible body, does not impart to
it any expansible power. The expansible
power of air existed before the compressing
force was applied ;
it existed from the instant
that the gas was formed, and the substraction
of the compressing force, has the effect only of
enabling the expansible body to expand with
greater freedom than before.*
* 1 hope to be excused from reverting again to this subject.
If any quantity of gas be made under water, the surface
of which is not an inch above the vessel in which the gas is
received, the gas will possess the same degrees of expansible
power, as if it were made in the open air. It will, I know,
be said, that the whole incumbent weight of thfe atmosphere
still exists. I allow that the atmosphere exists, but I deny it
exerts the weight which is ascribed to it. I appeal to the
B B
$70 CALORIFICATION.
Ought it then, I would ask, to be considered
a matter of surprise, that the immediate union
of the pure solar rays with opaque matter,
should be capable of producing all the phenomena
of combustion, and that the uncombined
state of the solar rays, which fall on the most
lofty summit of the most lofty mountains, should
be accompanied by volcanic eruptions; whether
they be situated at the polar or meridional
regions of the world. At those elevated points,
the rarity and purity of the medium affords
neither abatement to the power, nor resistance
to the motion of the solar rays ; the union,
therefore, which takes place with the opaque
matter on which they fall, may be supposed to
be of the most active kind.
SECTION III.
The Cause and Nature of Earthquakes.
These principles will more especially explain
the cause of earthquakes, of those violent
shocks of nature which take place, that develate
and tear- asunder the bowels of the earth, extending
far and near, and involving whole
proofs which I have offered in support of my opinion, as well
as to the demonstrative proposition, that a body which acts
equally in evtry direction, cannot act particularly in any one
direction.
CALORIFICATION. 371
districts in devastation and ruin. They will
more especially take place in those situations
of the world, where bituminous and sulphurous
strata and other substances exist,
constituting the pabulum with which the matter
of light may unite and become ignited.
In many countries it cannot be otherwise
: sulphur is often found to subsist in
collected masses in a native form, and the
quantity of kali and of wood, furnished by the
decomposition of vegetables that have perished
and decayed all furnish ingredients for the
formation of inflammable powder : a certain
degree of heat alone is necessary to ignite such
a mass. When we reflect on the quantity of
fire and of air which is evolved during the
process of fermentation, we shall readily admit
the efficiency of the means to produce the end:
wherever the strata of the materials I have
mentioned, subsist in great abundance, and
continue to great extent, I see no impediment
to the production of inflammation, manifesting
the phenomena of heat and of color, of
expansion the effect of ignition, and the consequent
explosion of the incumbent parts, undermining
and springing the foundations of the
strongest habitations, and involving them all in
one general wreck.*
*
I recollect in my early infancy, that there was a laboring
gardener, who used to entertain the little children of the neigh-
B B 2
372 CALORIFICATION,
I shall briefly detail one of the earthquakes
‘which took place in Italy, in the year 1 793,
the particulars of which have been so ably
related by the late Sir WILLIAM HAMILTON.
From the month of January to the month of
May, the atmosphere was generally calm, and
the weather dry ; and for several days before
bourhood, by mixing together different materials, and after
inhuming them to a considerable depth, an explosion or artificial
earthquake was, after a given time, the consequence. In
the lectures that are delivered by Professor Davy, at the Royal
Institution, I find that he exhibited the very same phenomenon
: he exhibited the model of a mountain made of clay,
in which was inclosed a mixture of potassium, filings of iron,
and lime. On pouring water into a fissure of this little mole
hill, violent combustion ensued, flame, and smoke were vomited
out of the little crater; boiling hot lava ran over the
surface, and spread over the side of the mountain; the whole
of which formed a most accurate exhibition of a volcanic eruption.
This very curious experiment was observed by the great
babies in petticoats and in breeches, as it had been done by
the little ones before^ with astonishment and universal applause.
It is very probable, that it was exhibitions such as
these, that led Dr. Enfield to observe ” that the hardy perseverance,
and the rigorous exertions which are necessary to
form the character of a philosopher, are so contrary to that
effeminacy and frivolity which distinguish the present age, that
if it were not for the provisions made in our universities, and
other seminaries for the propagation of sound learning, it is
to be feared that the more abstruse and difficult branches of
science would be excluded from the modern sstem of eduCALORIFICATION.
373
the shock took place, the water in the wells had
considerably diminished, some requiring ropes
of great length to reach the water, and in others
the water totally disappearing. About eleven
o’clock at night, the 12th of June, 1793, Sir
William says, “atNaples, we were sensible of a
violent shock of an earthquake which lasted
nearly half a minute ; it was more particularly
felt by the inhabitants of mount Vesuvius, who
all agree that the shock was from the bottom
upwards, after which an undulatory motion
was felt arising from the east and spreading
towards the west, and which extended upwards
of 30 miles from Naples. On the 15th of June,
soon after ten at night, another shock was felt,
but neither so long nor so violent as the former
one ; at the same moment, a fountain of fire,
attended with a very black smoke, and a loud
report, was seen to issue and arise to a great
height from out the middle of the cone of Vesuvius.
Soon after, another of the same kind
broke out at some little distance lower down,
as I suppose, by the blowing up of a covered
channel full of red hot lava. Fresh fountains
of fire succeeded one another hastily, and all in
a direct line, tending for about a mile and a
half towards the town of Torre del Greco. 1
could count fifteen of these, although I believe
there were many more, but which were obscured
by the smoke : it seems probable that all
374 CALORIFICATION.
these fountains of fire from the exactness in the
line of their direction, proceeded from one and
the same long fissure, one mile and a half in
length down the flakes of the mountain, and
that the lava and other volcanic matter, forced
its way out of the widest parts of the crack
from many mountains and craters. This fiery
scene was accompanied by the most horrid
noise; it was as the mixture of the loudest
thunder with incessant report like that from a
numerous heavy cartillery, accompanied by a
continual hollow murmur like that of the roaring
of the ocean during a most violent storm.
And added to this was another blazing noise
like that of the going up of a large flight of sky
rockets, similar to that which is produced by
the enormous bellows of the furnace of the
iron Carron foundry in Scotland. All that
time, there was not the smallest appearance of
fire or of smoke from the crater on mount Vesuvius.
But the black smoke and ashes issuing
continually from so many new mouths and
craters, formed an enormous and dense body
of clouds over the whole mountain, replete with
the electric fluid, making flashes of a zig-zag
form, called here Ferilli. Out of these gigantic
and volcanic clouds, I have seen balls of fire
issue and burst in the air: on the 16th, the
crater of Vesuvius showed signs of being on fire,
by some black smoke issuing out of it. At dayCALORIFICATION.’
375
break, issued another smoke tinged with red, increasing
until the whole was involved in fire,
in lightning, and in smoke. The ashes that fell
were wet, and to the taste very salt and pungent,
and contained many saline particles.
The breadth of the lava which fell into the sea
>
and which has now formed a new promontory,
after having destroyed the greatest part of the
town of Torre del Greco, is 1204 English feet,
its height above the sea 12 feet, and as many
under, 24 feet altogether ; and it extends into
the sea 626. I observed the sea water was
boiling as in a caldron where it formed the foot
of the new promontory, and smoked at 100
yards distance. I then put my hand into the
water, which was literally scalded, and the pitch
from the bottom of the boat was melting fast,
and floating on the surface of the sea ; a number
of boiled fish were afterwards found floating
on the surface of the water.” The horrid chasm
which Sir William found to exist two miles,
formed vallies 200 feet deep, and half a mile
wide ; and where the fountain of fiery matter
existed during the eruption it formed littlemoun
tains with deep craters. And he is of opinion
that 10,000 men, in as many years, could not
have altered the face of Vesuvius so much
was effected by this concussion, in the space of
four hours. He went on the top of some of the
most considerable of the new formed moun376
CALORIFICATION.
tains, and looked into their craters in circumference
about half a mile. Although the inte*
rior perpendicular height of many of them did
not exceed 200 feet, the depth of their inverted
cone within was at least 600, giving out sulphuric
vapours ; and in all there were depositions
of salt and sulphur. The ashes were
carried as far as Tarento, a distance of 25Q
miles, and as far as Lucca, which is still further
; and the Bishop of J)erry, in a letter
from Sienna in the Tuscan state, about 18 hours
after the commencement of the eruption, said,
that in the midst of a most violent thunder
gtorm, about a dozen stones of various weights
and sizes, fell at the feet of different persons ; the
stones of a quality, not found in any part of the
Siennese territory, one of which weighed 5lb. *
The torrents of water mixed with ashes and
mud that rushed from the summit of Vesuvius
to the adjacent countries carried with them
* It has become a question whether these stones have been
generated in this ignious mass of clouds, which produced such
universal thunder, or whether they were thrown from Vesuvius.
Is it not probable, that the different meteorological
stones which have fallen at different times, have arisen from
the same sources? and not from the disruption of mountains
in the moon, as the celebrated da Place, and others, have fancied.
It is, however, a curious circumstance, that these stones
are all combined of the same materials ; they are composed of
iron and of nickle, with a certain proportion of silex arid of
magnesia, a small portion of chrone and iron pyrites.
CALORIFICATION. 377
desolation and ruin. Sir W. H, is decidedly
of opinion that these floods were occasioned by
the sudden dissolution of watery clouds, the
air having been too much rarified to support
them. They, therefore, burst ; the water falling
from the air in streams, which, uniting with
fire, with ashes of a bituminous and oily quality,
and accumulating in pools to a great
height, at length forced its way into new
channels, and came down in torrents in countries
where it was least expected : composed of
scoriae, ashes, and stones, mixed with trees
that had been torn up by the roots : some of
the torrents were of the height of 10 to 40 feet,
carrying houses, walls, trees, and as it is said,
not less than 4000 sheep, with teams of oxen,
&c. &c.”
Whoever reads the sad history of the different
earthquakes, by which different parts of
the world have been visited, will be struck with
horror and with amazement: he will read of
large and populous cities, convulsed and shook
from their very foundations, buried and immured
to a considerable depth, with all their inhabitants,
the wrecks and ruins of which are
visible at this time. In the 17th year of the
Christian sera, under the emperor Tjberius,
Strabo relates that a dreadful earthquake took
place, in which twelve cities of Asia Minor
were destroyed in one night ; and it appears
378 CALORIFICATION.
from the remote situation of some of them, that
they must have occupied a circuit of 300 miles
in diameter. It is related by Gibbon, on the
authority of Ammianus, that the greatest part
of the Roman world was shaken by an earthquake,
that the shores of the Mediterranean
were left dry by the sudden retreat of the sea,
that great quantities of fish were caught by
the hand, and large vessels were stranded on
the mud. This state ofdesiccation was of short
duration ; the tide soon returned with the
weight of an immense and irresistible deluge ;
the effects of which were particularly felt from
the Sicilian to the Egyptian shores. Large
boats were transported on the roofs of houses,
multitudes of people were swept away by the
reflux of the water, and it is supposed that not
less than 50,000 persons lost their lives in the
inundation. Although there are few countries
extant, that have escaped these dreadful shocks,
there are many countries situated in the same
latitude, that seem particularly exposed^ to
them. The island of Jamaica has suffered and
been ravaged by them more than any of the
West India islands. In the year 1692, niuetenths
of the town of Port Royal, the metropolis
of that island, were destroyed by an earthquake,
in less than the short space of two
minutes : the houses sunk 30 or 40 fathoms
deep, the earth opened and swallowed up numCALORIFICATION.
379
bers of people, many of whom rose up in other
streets, as well as in the middle of the harbour.
One of the most destructive and extensive
earthquakes that is recorded in history, happened
in the year 1755, and as it proved more
particularly fatal to the city of Lisbon, which was
entirely destroyed by it, with 60,000 of its inhabitants,
it is generally known by the name of the
great earthquake of Lisbon. Although its violence
was more particularly felt in Portugal, it
extended not only over the whole peninsula, but
to Africa, and different parts of Europe ; covering
a tract of more than four millions of square
miles. The earthquake of 1782, which overwhelmed
the Neapolitan territory, destroyed
no less than 30,000 inhabitants, independently
of 6000 who died of disease, the natural consequence
of misery and alarm. The sad, but
interesting, detail of which has also been given
by the late Sir William Hamilton.
A variety of causes have been assigned for
these destructive effects by different philosophers,
and Dr. STUKELY, in particular, has
endeavoured to show that they were produced
by the electric fire, which tears up and rends in
pieces the bowels of the earth. That subterranean
fire is the proximate and immediate
cause of earthquakes, appears to be decidedly
proved by all the phenomena with which they
are accompanied. The fire not only forces
380 CALORIFICATION.
itself a passage through various fissures which
it makes, but converts a vast quantity of water
into vapor and steam ; by whose united aid,
the resistance of the incumbent mass of earth
is overcome, and a general overthrow produced,
attended with all the consequences which have
been detailed.
Some there are, who question the efficiency
in the means to produce the end ; and Di\
Stukely, in particular, supposes that the earthquake
in Asia Minor, which extended over a
circle of 300 miles in diameter, could not have
been produced by the explosion of the greatest
quantity of gunpowder that can be conceived ;
and he starts this objection for the purpose of
strengthening his favourite doctrine, of an elec-r
trie shock. According to my view of the subject,
both suppositions are perfectly compatible
; as the electric fire is a species belonging
to the same genus as fire in general, it is produced
by the same means, and produces the same
effect.
We have a multitude of facts to show that
the .solar rays, concentrated by means of a lens,
in an exhausted receiver, produce fire the most
intense, as well as on the summit of the most
lofty mountains : and it may be mentioned as
one, amongst other circumstances, which distinguishes
light from fire, that while we possess
the most ready means of concentrating to a
CALORIFICATION; 381
focus the solar rays, we have no such power
over the rays of fire ; the repelling power which
they manifest, eludes all attempts to their concentration
; wherever they exist, they become
the immediate cause of which the dilatation
of the surrounding parts are the effects ;
the effects which are produced bearing a certain
and definite proportion to the quantity and
intensity of the fire which is applied. It is very
probable, that the electric fire, in passing
through the earth, was the primary agent in the
ignition of the combustible materials, which
were involved within its bowels, and in accomplishing
the combination of the (latent) light
with them : the fatal and terrific effects of which
We have seen extended far and near.
Great and astonishing as the power must
Unquestionably be, by the agency of which
these awful and frightful effects were produced,
it is, nevertheless, very probable, that it falls
infinitely short of what it was at the beginning,
-at that memorable epoch, the moment of the
creation,- at that memorable epoch, when
the earth was without form ; that is, when
matter existed without figure, and when
void, and when darkness was on the face of
the deep,- of the deep, or of that immense
space between the waters below and the
heavens above, in which no air or atmosphere
existed to fill it, no light to illumi382
CALORIFICATION;
nate it, no fire to warm it, and in which nothing
subsisted but the omnipresence of the
Almighty, who ” moved with his spirit upon the
face of the waters.” When God said, Let there
be light, and there was light, it was not said,
let there be fire, let there be color, but it was
said, Let there be light ; at this eventful period,
a new order of things immediately arose, and
effects the most violent, it is to be supposed?
immediately followed ; although these effects
were produced through the instrumentality of
secondary causes, they emanated more immediately
from the energy of Almighty Power ;
and it is but reasonable to suppose, that those
effects were as infinitely greater, than any that
have since happened, as the power of God
transcends the power of man. If it be not
presumptuous to form a conjecture upon such
a subject, I should say that the union and combination
which immediately took place between
the light and the waters that were above the
surface of the earth, was followed by the conversion
of both into air ; that the action of the
light and air upon the opaque matter of which
the earth is composed, became the immediate
cause, of which fire was the direct and immediate
effect, the ultimate consequences of
which were felt far and near ; and that a general
disruption of the solid nucleus of the
earth, and a separation of the whole into two
CALORIFICATION. 383
separate parts, was thereby accomplished, with
the various subordinate divisions and separations
of those parts into smaller portions, as they
are found to exist in different islands, seas, &c.
that this shock was more particularly felt under
the line of the equator, where the solar rays,
from their vertical position, have the greatest
power; that by means such as these, two
great continents were formed ; the waters,
divided from the waters, and dry land appeared
; the whole fitted and adapted for the
habitation and residence of the infinite multitude
of animated beings, which were afterwards
created.
Whoever reflects on the effects which would
be produced on the whole planetary system, by
the intervention of the expansible bodies produced,
by the various meaons to which I have alluded,
will see the absolute necessity which exists,
that no part of them should ascend beyond
their proper bounds, but that means should exist,
by the operation of which they should be limited
and confined. Ifit were otherwise, if their
decomposition did not take place, there is every
reason to suppose that the whole mass of water,
of which the ocean is composed, would, in
the process of time, be evaporated, and converted
by the sun into a gaseous form ; the consequence
would not only be felt, by the state of
desiccation that would, long before this, have
384 CALORIFICATION.
Inken place on earth, but by the irregularity in
the motions of the whole of the planetary systeiti
that would inevitably have ensued* If the spheres
through which the different planets describe
their periodical revolutions, were rendered more
dense and resisting at different times, the regularity
of those motions would be perpetually disturbed,
and a total derangement of the whole
system of nature would follow. The providence
of God, therefore, by the supreme knowledge
of causes and of consequent effects, foreseeing
the disease, applies the cure; by the
agency of means, which not only preserve
harmony and order in the system of nature, but
which conduce to the preservation and support
of his creatures.
-CHAPTER XIX.
DECOMPOSITION OF ATMOSPHERIC
MATTER, ANP THE FORMATION OF
RAIN, ETC.
HOPING that I have been a fkilhful historian of
the phenomena which I have described, and
that I have succeeded in tracing, (as far as the
narrow span within which my abilities are confined
will admit,) those phenomena to their producing
causes ; it only remains that I should
point out the progressive changes which the at*
mosphere undergoes, when the parts, which
are converted from a liquid to a vaporific, and
gaseous state, are made to return back from a
gaseous to a vaporific, and, finally, to a liquid
one ; these causes may be principally referred
to combustion, to the absence of the solar
rays, to the changes of day and ofnight ; and
to the different seasons of the year. And finally,
to whatever cause by which the expansibility
of the atmosphere is weakened or destroyed.
This loss of expansibility which the air
c c
86 ATMOSPHERIC MATTER.
suffers by combustion is proved by the decomposition
of the water out of it. We have the fact
proved in a general way, constantly before our
eyes, by the depressions which the mercury of
the Eplanometer sustains in a storm, and its
elevation in a calm, in a wet and in a dry day ;
sinking, more especially in tropical climates,
where the periodical changes which take place
in the atmosphere, are more evident, and considerable,
than they are in lower latitudes, the
mercury sinking from the elevation of 31 to 27
inches; and in this country, from 30 2-10
to 28.
The reduction of the expansible force in the
atmosphere is observable at night, by the absence
of the solar rays, more especially in the
summer season, when we behold a large proportion
of the water which had been during the
day, absorbed and gasified, return during the
night from gas to vapor, from vapor to moisture,
or dew. It is owing to the decreased degrees
of expansibility in the atmosphere, in
consequence of its increasing dilatation from
the surface of the earth, to the more elevated
regions, that from being clear and transparent,
it is found to terminate in a turbid or
foggy state, known by the name of clouds ; so
that the transmutations which we often behold
clouds and fogs undergo, from dryness to
moisture from levity to weight from suspenATMOSPHERIC
MATTER. 387
sion and balance, to precipitation and fall, are
merely different stages and degrees of one and
the same process ; or, in other words, the state
of levity which the watery particles had ao
quired, while they subsisted in a gaseous state*
become progressively impaired, or lost ; they
become relatively heavier than the rare medium
in which they are situated ; they therefore obey
the laws of relative weight, and in their descent
through the air, they become compressed and
shaped in different forms, increasing in magnitude
as they approach the earth ; they fall on
the surface, and are known by the various ap
pellationsof rain, of hail> and of snow. These
spontaneous changes, which take place in the
atmosphere, may in a limited degree be iim^
tated by art, and are followed by the same
consequences. The expansibility of the atmospherical
air may be weakened by combustion,
as well as by being rarified and partly exhausted,
as in the air-pump ; such is the dilatation
which, the residuary air has in consequence
sustained, that its power of supporting the
aqueous particles becomes progressively and
proportionably weakened : after a few strokes
of the piston, a very sensible change in the
decomposition of the air becomes perceptible
; from being transparent and dry, it becomes
turbid and moist ; and when the exhaustion
is made as complete as it is st*sceptible of,
cc 2
388 ATMOSPHERIC MATTER.
a dewy moisture is observable trickling dowra
the internal surface of the receiver.
By the united combustion, in close vessels
of different gases, more especially of oxygen
and hydrogen gas, the same phenomena
take place : from being transparent and clear,
they become clouded and foggy ; from a state
of dryness, they become moist; such is the
degree of decomposition in them, which by the
combustion has been produced, that in the
space of about an hour, nearly the whole of the
water which the gases contain, is separated out
of them, and precipitated from them to the
bottom of the receiver.* This experiment,
which is neither more or less than a petty imitation
of the change which takes place in the
great laboratory of the atmosphere, by the
effect of lightning, has occasioned as much
clatter among experimentalists throughout the
world, as if they had discovered the philosophers’
stone ! !
* Under both circumstances fire is produced, manifested
by color and heat ; in both the water which was either suspended
and diffused, or actually gasified in these airs, becomes
decomposed and deposited out of them.
4Q98
CHAPTER XX.
-ON COMETS: o, THE MEANS BY WHICH TH
MATTER OF ONE SYSTEM IS PREVENTED
FROM INTERFERING WITH THE MATTER
OF ANOTHER.
THE different means which I have hitherto detailed,
by which the expansibility of the atmos*-
phere is limited and bounded, are parts only of
one general plan ; they are links belonging to a
chain of causes, which the GOD of Nature has
established, from the beginning of time, to the
end of it, by which not only the most minute
particles of matter belonging to our system,
but also that of the whole galaxy of heaven,
is regulated and governed. Obvious and
sufficient as those means appear to be, to prevent
the most dense and solid parts of this earth,
from ascending and interfering with the spheres
of other worlds, they are inadequate, and insufficient,
I apprehend, to confine, and to
bound within its proper limits, such portions of
the atmosphere as had been divested and stript
390 COMETS.
of their grosser particles. From the essential
property of expanding which these parts possess,
and from being situated in a medium
which affords to their expansible power little
or no resistance; it is a matter of necessity as
an effect immediately flowing from cause, that
the air, in its upper regions, should, in that
case, dilate to its utmost possible extent, and
diffuse itself to the uttermost regions of
space; so that all the materials on this earth,
which subserve to the . process of vaporisation,
would long before this period, have been dissipated
and elevated to distant worlds ; if there
did not exist means, by which those consequences
are prevented. We are, therefore,
driven to the necessity of searching for those
instruments, which a vigilant and protecting
Providence employs, and by which these deleterious
effects are effectually averted.
Without the existence of such instruments,
the whole economy of nature, would be subverted
and destroyed ; the planetary spheres
would be polluted, and penetrated by a constant
interchange of materials; they would
be rendered more dense, and more rare, at
different times. The planets, whose motions
are so regular and precise, would be either
accelerated, or retarded, in their course;
and neither their times, nor their revolutions,
could be anticipated, or ascertained.
COMETS. 391
It forms a part in the great scheme of Providence
in the physical government of the universe,
so long as it shall please God, that that
universe shall continue to exist, that those evils
shall not take place, they are prevented from
taking place not by the annihilation of matter,
but by the decomposition of it ; by bereaving
it of those powers of expanding, which it
had factitiously obtained, Whence (it may be
asked) are the means, through the agency of
which the end is obtained ? They are before the
eyes ofall, and are generally understood. It is
generally understood, because it is a general
fact, that the expansibility of air is weakened
and destroyed, by combustion ; whilst the base
of which the air was composed, becomes separated
from the light, the light is given out, as I
have before explained, in a calorific and colorific
state; and it may be presumed that by an extension
of the same process it becomes purified
from the dross with which it had combined,
and is returned back to the sun itself, from
whence it was derived.
It was from a course of investigation such as
this, that so long as eighteen years ago, I was led
to conclude, that COMETS were the instruments
which were employed to perform this beneficent
purpose ; that they were bodies which formed
the Jines of separation, and of demarkation*
between the planetary spheres : proclaiming
392 COMETS,
the voice of God, With a Tongue of Fire, lo the
matter of the earth, and of the whole planetary
system,
” Thus far shal t thou go, but no farther.”
With a reverential belief at that time, in the
whole truth of the Newtonian hypothesis, (unnatural
and artificial as it is,) I was, nevertheless,
led to conclude, and to publish, that
Comets, ivere bodies, which were destined to perform
the office, which I have above described ;
that they were destined to decompose through
the medium of combustion, whatever gaseous,
or atmospheric materials, had ascended
beyond their proper bounds ; that instead of
being limited, as I understood was the case, to
nine only, I was persuaded, that they were as
indefinite in point ofnumber> as they were in magnitude.
Instead ofdescribing regular orbits, that
they must be altogether irregular in their motions:
and finally, that instead of being permanent bodies,
and returning at stated periods, they were
transient and evanescent ; were finally dissipated
and decomposed, and no more seen. I, therefore,
ventured to affirm, that the uppermost limits
of our atmosphere, I teas persuaded, abounded
with them ; and that it was only a proof of the
insufficiency and imperfection of our instruments,
that they were so seldom discovered; that they
were in their nature fiery, like other meteors,
like lightning^ and other species offire, differing
tinly in quality, in consequence of the difference
COMETS. 393
fin the subtilty and nature ofthe materials ofwhich
they were composed, and that there were sublunary
Comets ; that iftlwre were Comets amongst tJie
higher planets, it thpetv some light on the nature
of the matter of which those planets were composed,
as it shewed, that they possessed an atmosphere
like our own, of a combustible nature ;
that it was probable their atmosphere was infinitely
rarer and purer ; and, consequently, that
the Comets subservient to the preservation of
ihe purity of their spheres, must move infinitely
more rapidly, and the lustre which they displayed
must be infinitely more brilliant, than those of a
sublunary nature.
Destitute of facts, by which those conclusions
were founded, they could only be considered
as unsupported assumptions from which
I had formed an hypothesis; I reasoned from the
necessity of the case, and not from any astronomical
knowledge which I possessed ; the late
Mr. GEORGE ADAMS, who was a good practical
astronomer, told me, in a conversation which I
had with him on physical subjects, that he had
been much struck with the deductions which I
had made, respecting the nature of Comets ;
for although it seemed as if I thought that nine
only existed, he could assure me, there were
many more ; and that M. MESSIER in particular,
of Paris, was nicnamed the Comet finder, in
consequence of the number of Comets which h<*
394 COMETS.
pretended to have discovered. Six months
after this, DI-.HERSCHELL published a paper in
the Philosophical Transactions, which tended,
in a great measure, to confirm, by facts, the
deductions which, from hypothesis?, I had made.
Of those bodies which I was ignorantly taught
were limited by astronomers to nine, but
which J ventured to assert very generally
existed in the upper regions, Dr. Herschell
says,
” Many of the operations of nature
are carried on in her great laboratory, in a
manner which we cannot comprehend ; but
now and then we see some of the tools, with
which she is at work. We need not wonder
that their construction should be so singular,
as to induce us to confess our ignorance of
the method of employing them ; but we may be
assured, that they are not a mere lusus naturce.
I allude (the Doctor goes on to say) to the great
number of small telescopic Comets, that have
been observed ; and to the far greater number
still that are, probably, much too small to be
noticed by our most diligent searchers after
them. Those six, for instance, which my sister
has discovered, I can, from examination, affirm,
had not the least appearance of anjr solid
nucleus, and seemed to be mere collections of
vapors, condensed about a centre. Five more,
that I have observed also,were nearly of the same
nature. This throws a mystery over their desCOMETS.
M 395
filiation, which seems to place them in the allegorical
view of tools, probably designed for
some salutary purposes to be wrought by them;
and whether the restoration of what is lost to
the sun, by the emission of light, the possibility
of which we have been mentioning above,
may not be one of the purposes, I shall not presume
to determine.”
I respect Dr. Herschell too much to accuse
him of plagiarism. It is, however, a little extraordinary,
that this paper should have been
presented to the Royal Society, a few months
only, after my book was published : and that in
this paper the Doctor ascribed to lightning, meteors
and cornets, the very use which I had done
before : that I should assert the necessityof their
existence; and that the Doctor should afterwards
declare, that he saw them, that they were
composed of the same kind of matter as I had
asserted, and that they were designed for the
same use. Without wishing even to suspect
that Dr. Herschell had seen my book, I think
it just to say, that the truth of my hypothesis
is strengthened by Dr. Herschell’s opinion,
and confirmed by his discoveries.
Reasoning, as I did, from universals, it became
a matter of necessity for me to inquire
how far the particular facts, justified the universal
conclusion. I, therefore, consulted the
various histories which have been given by dif396
COMETS.
ferent astronomers, of the different Comets that
have made their appearances at different times;
and from their testimony it appears, that neither
their revolutions, nor the periods of their return,
have ever been ascertained. If the motions of
Comets were regulated and governed by the
same laws which regulate and govern the planetary
system in general, the expectation of those
who have anxiously looked for the periodical return
of individual Comets, would not have been
disappointed; neither would the system of the
universe continue to exist, without some of the
parts sustaining violent and dreadful shocks,
from the violent appulse which those parts would
have sustained from the immediate contact
between them and Comets. The Comet which
has caused the greatest alarm to the inhabitants
of the earth, and been supposed to threaten it
with a visit, was the one of 1680. Dr. HALLEY,
by calculation found, that Nov. 11, 1680, at
1 h. 6m. P. M. it was not above one semidiameter
from the earth ; and had the earth, it is
said, been at that time in the part of her orbit
nearest to the node of the Comet through
which it passed, their mutual gravitation must
have caused a change in the plane of the orbit
of the earth, and in the length of our year :
and Dr. Halley adds, that if so large a body,
with a motion so rapid, as that of this Comet
nearest its perihilion, were to strike against our
COMETS.
globe, (a thing he conceived by no means impossible,)
the shock would have been so great,
as to have reduced this beautiful frame to itsoriginal
state of chaos ! M*
The Comet which was observed by APIAN,
In 1531, which KEPLER described, in 1607,
and which Dr. HALLEY supposes he observed
in 1682, and predicted would return about the
5th of April, 1758-9, is the only instance on
which the expected returns of Comets can be
justified. It is very true, that Dec. 14, 1758, a
Comet did actually appear. When we reflect,
however, on the multitude of those erratic bodies
which have been since discovered, it is no
wonder, that in the anxious expectation of the
fulfilment of the prediction ; when all the astronomers
were exploring every point in the
heavens, another Comet should have been
discovered ; and that this new Comet should
be supposed to be the same identical one that
had appeared 150 years before. The Comet,
however, of 1 770, whose period was supposed
to be five years seven months, has never since
appeared.
* How vain are those, fears, how fanciful those conjectures
1 From the history of Comets which we possess, it
appears decidedly to be proved, that instead of describing
complete revolutions, they are consumed and dissipated, long
before any one revolution is completed ; and, consequently,
that their return can neither be anticipated, or ascertained.
398 COMETS.
DE LA HIRE, and other astronomers, are of
opinion, that Comets never return. CASSINI,
and others, think it probable that they do ;
but NEWTON, HALLEY, FLAMSTEAD, and the
generality of the English astronomers, bigotted
and rivetted to their own system, are persuaded
that they have their regular periods,
although they are not so well ascertained, as
those of the planets. De la Hire, and Cassini,
observed a Comet in 1698, which they supposed,
from the velocity of the motion, and the
path which it described, to be the same as was
seen in 1 652 ;
its period appeared to have been
43 months ; and the number of revolutions from
1652, to 1698, they supposed to have been 14.
It is, however, very justly observed, that in an
age wherein the heavens are so narrowly
watched, it is hard to beHeve, that a Comet
such as this, should make, unperceived, 14
revolutions ; more especially as a Comet of that
description, might appear visible above a
month together. The Comet of 1702, viewed
by Cassini, and which he concluded to have
been the one seen in 1668, giving it a period of
36 years, has never again appeared, more than
a variety of others that might be mentioned.
Dr. Halley suspected that the Comet observed
by Apian, in 1532, was the same Comet as
had been observed by Hevelius, in 1661 : if
COMETS. 399
that had been the case, it ought to have returned
in 1789, or 1790, which it never did.
From the earliest periods, a variety of Comets
have appeared, that were neither anticipated
nor expected ; and whose motions and appearances
have born neither analogy nor resemblance
to the history which has been given of
those of former times. The history of the Comet
described by Hevelius, in 1661, perhaps,
conveys the most precise idea of the change
which it is presumed Comets undergo. Its
body was of a yellowish color, very bright and
conspicuous, but without any glittering light ;
in the middle was a dense, ruddy nucleus, almost
equal in size to Jupiter, encompassed with
a much fainter, thin matter : Feb. 5, its head
was somewhat bigger, but its light more dusky,
than the rest of the stars ; here the nucleus
appeared divided into several parts. Feb. 6,
the disk lessened, the nuclei still existed, though
less than before ; one of them on the lower part
of the disk, much denser and brighter than the
rest ; its body round, and representing a very
lucid little star ; the nuclei still encompassed
with another kind of matter. Feb. 10, the
head somewhat more obscure, the nuclei more
confined, but brighter at top than at bottom.
Feb. 13, its head diminished, both in magnitude
and brightness. March 2, its roundness
a little impaired, its edges lacerated. March
400 COMETS.
g8, very pale, and exceeding thin ; its matter
more dispersed, and no distinct nucleus at
all appearing; and I shall only revert to*
the Comets alluded to before, which Dr.
Herschell discovered^ and which he was in-*
timately persuaded to be mere collections
of vapors, condensed about a centre, without
any nucleus whatever ; to show the probability
which exists, that Comets are nothing more than
atmopheric matter, in a state of combustion.
The rapidity and intensity of the combustion
which is thus going on in Comets, may, in some
degree, be estimated from the colorific, and calorific
rays, which issue from them. Two
Comets described by JUSTIN, lib. 37, according
to his account,
” shined so bright, that the
whole heaven seemed to be on fire, and by their
greatness filled up a fourth part of the heavens,
and by their splendor exceeded that of the
sun ; and it is affirmed, with regard to the
Comet of 1401, that the sun being got below
the horizon, there appeared in the west,
a bright and shining Comet, sending out a
tail, upward, in splendor like a flame of fire,
and in a form like a spear, darting its rays
from west to east ; by the lustre of its own rays,
it enlightened ail the borders of the earth, not
permitting the other stars to show their lights,
or the shades of night to darken the air, because
its light exceeded that of the others, and
COMETS. 40 T
extended itself to the upper part of the heavens,
flaming.* Exaggerated as these descriptions
may seem, they were almost equalled by the
appearances of the great Comet of the year 1680.
With all the phenomena which belong to
Comets, it appears that they are bodies consisting
of materials in a state of violent combustion,
and that they are not what Sir I.
NEWTON supposed them to be,
”
solid, compact,
and fixed, and durable bodies, Mke the
bodies of the planets ;” for he goes oa to say,
” If they were nothing else but vapors^ or the
exhalations of the earth of the sun, and the
other planets : this Comet, in its passage by
the neighbourhood of the sun, would have been
immediately dissipated;” for Sir Isaac assumed,
that the heat of the sun, is as the density of its
rays, that is reciprocally as the square of the
distances of the place from the sun. Therefore,
since on Dec. 8, when the Comet was in its perihelion,
the distance thereof from the centre
of the sun, was to the distance of the earth
from the same, as about 6 to 1000, the sun’s heat
on the Comet, was at that time, to the heat of
the summer’s sun with us, as 1,000,000 to 36;
or as 2.8,000 to 1. But the heat of boiling water
is about three times greater than the heat
which (Jry earth acquires from the summer
* His. Byz. Due Mich Nepot.
D D
402 COMETS.
sun, Ihave tried; and the heat ofredhot iron, (if
my conjecture is right,) is 3 or 4 times greater
than the heat of boiling water. And, therefore,
the heat which dry earth, on the Comet, while in
its perihelion, might have concord from the rays
of the sun, was about 2000 times greater than the
heat of redhot iron. But by so fierce a heat,
vapors and exhalations, and every volatile matter,
must have been consumed and dissipated.
This Comet, therefore, must have conceived
an immense heat from the sun, and retained
that heat for an exceeding long time ; for a
globe of iron, of an inch in diameter, exposed
redhot to the open air, will scarcely lose all its
heat in an hour’s time; but a greater globe
would retain its heat longer, in the proportion
of its diameter, because the surface (in proportion
to which it is cooled by the contact of the
ambient air,) is in that proportion less, in respect
of the quanity of the included hot matter ;
and, therefore, a globe of redhot iron, equal to
our earth, that is, about 40,000,000 feet in diameter,
would scarcely cool in an equal number
of days, or in above 50,000 years.”*
So far, however, from subscribing to the
opinions that were entertained by Sir Isaac
Newton, that Comets are compact and solid,
fixt and durable bodies, like what he
supposes the planets to be ; I conceive that
they are composed of the rarest materials
*Davis’sTranslation of Sir I.Newton’s Principia, vol. 2. p. 285*
COMETS. 403
possible ; instead of deriving their fire and
splendor immediately from the sun, I conceive
that the fire and splendor which they display,
are effects only which are produced by the
union which has taken place, between the atmospheric
materials of which they are composed,
and the solar rays, with which they
have combined, that those pure rays ; being
destitute of fire altogether, could not convey
into the bodies of the Comets, any quantity
whatever of fire into them ; and, consequently,
that the various calculations that have been
made respecting their motion, and situations,
from the nature of the materials of which it is
supposed they consist, are altogether erroneous
and fallacious ; as erroneous and fallacious
as the supposed limits which have been
given to the elevation to which it is conjectured
our atmosphere extends. I conceive it as impossible
to measure the extent of it by means
of the barometers which are employed, as it is
for the barrow-boy in the streets, who sells
filberts by the pound, to measure in his scales,
the relative densities and weights of the planets
Jupiter and Saturn.
In order to bring my ideas, respecting
the nature of fire, to a close, I shall take
leave to observe, that I conceive the sun to
be neither hot nor cold, but to be constituted
of light only ; that the rays which perpetually
emanate from the sun as their source^
304 COMETS.
constitute the purest and most active species of
matter which exists, or of which we have any
knowledge ; that as they proceed from the
sun, they are perpetually combining with the
opake and atmospheric matter with which they
come in contact, producing the various phenomena
of Comets and meteors, lightning, culinary
and atmospheric heat. That it is by the
chemical union of this matter of light with
atmospheric matter, that heat, or fire, is first generated
; that this pure matter of light, or solar
rays, I conceive, constitute the caloric of the
present chemists ; that it is by the combination
of this light, or caloric, as they call it, not by the
decomposition of it, that sensible heat, or fire, is
produced, possessing properties in its combined
state, very different from what it did in
its simple one ; in its pure and uncombined
state it is analogous to what is absurdly
called latent heat ; in its compound, or combined
state, it is called sensible heat, or fire.
CHAPTER XXL
ON THE LAWS OF MOTION.
AFTER the different properties, which have
been shown essentially to belong to the solid and
to the liquid to the expansible and elastic
matter of which the world is composed ; it will,
I trust, be readily admitted, that instead of
being one and the same, they are altogether
and absolutely different from each other. If a
general review of the whole system of nature
indeed be taken, it will lead us to conclude, that
a regular chain, of order and of subordination
subsists not only in the common matter of
which it is composed, but also in the various
orders of animated beings it contains.
The analogy that subsists between the different
links of this vast chain is so close, and their
gradation so easy, that it is often very difficult
to say, where the one ends, and the other begins
; what are the different marks by which
406 LAWS OF MOTION.
some parts of the animal kingdom are distinguished
from the vegetable, and some species
of the vegetable from the animal, until its final
termination in the human species. Although
the relation and similitude which the various
individuals bear to the species, as well as the
different species to the same genus, are great
and striking; there, notwithstanding, subsists
shades of difference between every part; so
that when the extremes are compared, instead
of analogy, there is a total difference between
them. Vast and immense as the chasm actually
is which separates both, it, notwithstanding,
is filled up by a regular procession of be*
ings, both animal and vegetable, until it finally
terminates again in inanimate and formless matter;
all possessing different powers, faculties and
aptitudes, concatinating the two extremes : the
perfect with the imperfect, the rational with the
irrational, the active with the passive, the simple
with the compound, the organised with the
disorganised ; until we arrive at, and are forced
to acknowledge, the existence of elementary
matter, of which the universe is composed and
filled, as manifested by the regular gradation in
the elements of light and air, of water, and of
earth.*
* From what has been said, it will appear, that I do not
.consider air as an original element, but as a compound, which
LAWS OF MOTION. 407
It has been in direct violation of these self-
-evident truths, of the absolute and essential
-difference which exists in the different species
of matter existing in the universe, that the
Newtonian laws of nature are founded, 1. By
supposing that reaction was always equal, and
contrary, to action, he has confounded capacity
with power things inanimate with animated
beings, and demanded a condition of
things to exist, which has no existence, space
without matter. 2. By insisting on the doctrine
of universal gravitation, he has confounded under
the same law, bodies whose properties are toto
coelo different from .each other; toe has not
only confounded matter solid and fluid, opake
and rare, active and passive, but even extended
this unnatural law to the whole planetary
system ; and finally concluded, that the motion
of the heavenly bodies are governed by the
same laws as the rotten apple that fell from
the tree in his garden, and which laid the foundation
for the whole of the system. Had that
has been formed, and which serves as a connecting medium,
between the solid and the liquid parts of the earth, and the
matter of light. An element, strictly speaking, is not produced
by any composition ofdifferent species of matter; but
becomes the primary agent, in the process of composition ; or
as JOHNSON elegantly expresses it,
* It is the first and constituent
principle of any thing.’
408 TLAWS OF MOTION.
tree, however, been immersed in water, and
not in air, instead of the apples falling to the
ground, they would haVe risen to the surface of
the water, and, it is probable, that we should
not have had at this day to complain of the
universal principles which have been formed
from a partial solitary fact. After having endeavoured
to prove, that gravitation is only a
relative, and not a positive term ; and that reaction
cannot be equal, or greater than action ;
but that it must be less ; I shall now proceed
to show, that the two remaining laws on which
the Newtonian philosophy is founded,, are
equally unnatural and erroneous, and that they
only require to be examined, in order to be
exposed.
Lex: Corpus onme persevare, in statue suo
quiescendi vel movendi uniformiter in directurn,
nisi quatinus, a viribus impressis cogitur
statum ilium mutare ; or, in other words, that
”
every body will persevere in its state of rest, or
of uniform motion, in a right line; unless it is
compelled, by some force, to change its state.”
1st. Although this pretended law is applicable
to solid matter only, whenever it is made to
undergo a change from rest to motion, and from
motion to rest, it will appear to be altogether
irrelevant, when it is applied to the government
of the essential property either of air, or of fire,
and more especially of the solar rays ; it is not
LAWS OF MOTION. 409
Vine that either of these bodies are naturally
disposed to persevere in a state of rest, more
than solid matter can persevere in a state of
motion in a right line, unless compelled to
change that state by some external force.
These bodies are essentially active, and when
left to follow their natural power, are in perpetual
motion; so far from persevering at rest,
unless they are moved by a force impressed
upon them, they require a force to be impressed
on them, to prevent them from moving, the
power by which they are able to move, with a
Velocity so immense as they are found to do, is
not derived, but is inherent ; it does not proceed
from external impulse, but from internal
energy ; not vi effecto, but causa motns ; not
from any active, or repulsive, power in the
bodies on which they fall, and from whence
they are reflected ; but owing to an innate quality
which they derive from the source out of
which they emanate.
However admissible the assertion might
be, that the motive power of the sun itself,
might impel the rays from its surface, with a
motion sufficient to traverse the whole of the
planetary spheres ; it is impossible to ascribe
the reflection from inert surfaces on which these
rays have fallen, to any power which those surfaces
possess because a passive body can
never be the cause of action ; nor can motion
410 LAWS OF MOTION.
be effected by a body which is impassive and
immotive. The reflection, therefore, from different
surfaces, which the solar rays are known
to undergo, cannot be produced by any power
inherent in those surfaces, but must be referred
to the self-motive power of the rays alone, by
virtue of the elasticity they essentially contain ;
neither the solar rays, light, fire, nor air,
are indifferent to motion, or to rest ; they are
passive by the influence on them of an external
force, they are self-motive without it.
2d. Neither is the assertion justified by the
fact, that these bodies can ”
persevere in a state
of motion in a right line.” Such is the natural
existence of things in the world, that the matter
of which it is composed, has a constant tendency
to oppose resistance to the motion of a
body passing through it, and which resistance
alters the line of direction which the moving
body would otherwise pursue. The rays of
light are perpetually converged and diverged
from the influence of the medium through
which they pass, and seldom, if ever, move in a
right line. The same variation takes place in
bodies which are impelled to move by an external
force ; the influence of the medium through
which they pass, alters the direction of their
motion, from a right line to a curve; and on
the Newtonian hypothesis itself, the planets describe
curves, and not right lines.
3dly. To suppose that bodies persevere in a
LAWS OF MOTION. 411
of rest, or of motion in a right line, is to
suppose that which never has, and never can
happen; it is necessary to suppose, that there
are situations in which no external agents are
present ; or, if present, that they exert on them
no influence whatever; either that space exists
without matter, or matter without resistance:
a supposition such as this, is not only
without proof, but contrary to proof; a mere
petitio principii; so far, however, from acceding
to the truth of it, I reject, as inadmissible
the principium petitionis ; I reject altogether
the proposition, which requires for its
accomplishment the annihilation of all the
gaseous, the liquid, as well as all the solid
matter of which the world is composed ; for
so long as matter, such as this, continues to
exist, not only the direction in a right line,
which a moving body would describe, will be
perpetually changed, and the motion itself be
ultimately arrested; but the moving body thereby
”
is from necessity,” and by a sensible and
obvious force,
”
compelled to change its state.”
And the law ofnature is that as obstacles constantly
intervene, a body once put in motion
cannot move for ever in a right line.
The necessity which a moving body is
compelled of changing its line of motion, in
consequence of the nature of the medium
through which it is impelled, proves that the
.second Newtonian proposition, or law, is not
412 LAWS 6
correct : Mutationem motus proportionaletn
esse vi motrici impressae, et fieri secimdum
lineara rectam qua vis ilia impremiter : namely,
that the mutation of motion, is always
proportionate to the force impressed, and is
always made according to that right line in
which that force is impressed.” However true
it may be, that a given force impressed upon a
body, will give it a given motion, under the same
circumstances of external resistance, it must,
nevertheless, be acknowledged, that the same
force, impressed upon the same body, under
unequal degrees of external resistance, will not
excite on it the same degree of motion ;- the
same force acting on the same body, will produce
a very different result, in a rare, to what
it does in a dense medium ; in air, to what
it does in water; in water, to what it does
when resisted by the solid nucleus of the
world, in which the resistance is so great, that
the same given force, acting upon the same
body, will produce no motion whatever. It is
the resistance which exists which not only tends
to change the direction of the force, by which a
body is moved, but to destroy motion altogether:
the assertion, therefore, is not just, that
the mutation of motion is always proportionate
to the force impressed ; the mutation of motion
depends on the relation which exists between
the force, and the resistance which is opposed
by the body which is to be moved ; neither is
LAWS OF MOTION. 413
the motion produced precisely in the direction
of that force.
4th. Admitting, however, by hypothesis,
what is false in fact, that external resistance
can be abstracted and removed, by the annihilation
of all the matter which filled the medium
through which the moving body was to pass,
I contend that no body whatever, which had
been excited to move, would move for ever,
that is ”
persevere in its state of motion.” A
proposition such as this, is false in fact; because
obstacles constantly exist to retard, and
ultimately to destroy, that motion ; these obstacles
not only reside in the medium, but in the
essential attributes of inertness, and of immobility,
which inheres in the solid matter which
is intended to be moved ; and these attributes
of inertness and immobility, constantly tend to
weaken, and to destroy, the energy of this moving
power. It is to the nature, and to the
efficacy, of the moving power, that is to be
ascribed the motion which is accomplished ;
in order that motion be produced, it is absolutely
necessary that the power should be
active, and that the thing moved should be passive.
And, finally, to produce motion perpetual,
(i. e. perseverance in a state of motion,) the
power must not only be active, but active infinitely
; and the matter moved not passive only,
but passive infinitely.
414 LAWS OF MOTION.
It is demonstrable, that if the agent is finite,
the motion on another body, which that
agent produces, must be finite also, because a
finite power cannot produce an effect which is
infinite. If all the metal which has ever been
separated from the bowels of the earth, were
fused and formed into one gun ; if all the gunpowder
which had ever been manufactured,
were rammed into it; if all the balls that have
ever been made, were melted into one, and
placed upon the powder ; however grand and
terrific the explosion might be ; however far
the ball might be projected, such is the resistance
alone, which would be opposed by the
ball (or the body moved) to the repulsive power
of the gunpowder, that its energy would be
progressively diminished, and be ultimately
destroyed ; and as a natural consequence of
the loss of this energy in the moving power, the
body which had been moved by it, would gradually
verge from motion to rest, and ultimately
become passive and inert.
I would, therefore, call on those who are
disposed to defend this double proposition, to
point out to me, not only where space without
matter is known to exist ; and matter without
resistance; but the finite power which can
produce an infinite effect, an effect which
would, in such a case, not only be different
but better than the cause, whose motion would
LAWS OF MOTION. 415
continue after the energy of the moving cause
was altogether lost. An hypothesis such as
this may subserve the purpose of fiction, not of
truth, and ought not to have been assumed as
the basis, from which the phenomena of nature
are to be explained ; since these phenomena
subsist, independently, and in direct violation
of it. If the whole matter of which the universe
is composed, were in its nature of the
same species as the granite, ofwhich the principal
portion of the nucleus of the earth is formed:
the attraction of gravitation arising from the
quantity of matter might, perhaps, be assumed.
If the solar rays did not radiate throughout the
whole of the planetary spheres, the existence
of a vacuum might, perhaps, be inferred. If
expansible bodies did not dilate by their own
inherent power, to the utmost possible extent,
Comets might be supposed to be bodies fixed,
solid* and opake. If matter did not oppose resistance
to the motion of bodies through it, it is
possible that every body might persevere in its
state of rest, or of uniform motion in a right
line. If all bodies, instead of being active and
passive, were all essentially active, instead of a
plenum, a vacuum existed, it is possible that
reaction might be equal to action. If the sun,
instead of being (what it is reasonable to believe
it is,) a globe of pure light, were a globe
of burning fire, mathematical principles could
41 () LAWS OF MOTION.
ascertain the degree of ice, and of cold, which
existed in Saturn ; of fire and of warmth in*
Venus: and if fire itself, instead of being a
body, the most repulsive, that exists throughout
the whole system of nature, were what it is
not ; if fire were an attracting body, it mighty
in that case, be assumed, that the sun constituted
the attracting centre of the whole planetary
system. If the supposition could be admitted,
which the testimony of all men, of common
sense, in all ages, have absolutely denied
; if it were admitted as a truth, that giants
and pigmies had an actual existence, all the
fictions recorded by that most ingenious man,
DEAN SWIFT, in the celebrated history which
he has given of those renowned kingdoms,
Brobdignag and Lilliput, must be admitted as
incontrovertible truths ; all the phenomena
which took place, may be legitimately deduced
from the principles assumed. So it is, in fact,
with the Newtonian philosophy. If the definitions,
and the laws, contained in thePrincipia,
are once admitted as axioms, or self-evident
truths, which proclaim the attributes which belong
to the different species of simple, and of
compound matter ; the whole chain of events
which take place throughout the whole system
of nature, may be satisfactorily explained.
The relative distances in which the different
planets are situated, as well as the velocity of
LAWS OF MOTION.- 417
the motions which they describe may be ascertained.
It is of importance, however, to observe,
that it was not from a previous knowledge
of the quantity and quality of the matter
of which the planetary system is composed,
that Sir I. NEWTO& discovered, and ascertained>
the times and the revolutions of its difr
ferent parts; but he inferred from the times
which the different planets take to describe
their revolutions, the quantity, as well as the
quality of the matter, belonging to them alL
No conclusion was ever made from a more faU
lacious, or more unphilosophical assumption.
It is not because the indexes of a watch, and of
a clock, describe equal areas in equal times, that
they are necessarily moved by one and the same
cause. A good mathematician, who beholds the
regular motion of the index, round the dial plate,
is able, by means of proper instruments, to ascertain,
in a manner the most precise, that
it moves over the space of an inch and a
half, in one hour’s time ; amounting exactly to
eighteen inches in one day. In like manner, a
good astronomer, by observation, and the aid
of instruments, is able to ascertain, the different
times which the different planets take to
perform their revolutions. Although the mathematician,
and the astronomer, are able by
these means, to ascertain the times and the motions
of these different bodies, the causes of
E E
418 LAWS OF MOTION.
those motions are objects which, in their natureare
altogether separate and distinct ; the motion?
of the index may be caused by the elasticity of
steel, as in a watch ; or by the density and
weight of a piece of iron, as in a clock. The
science, however, which treats of the one, is
entirely separate and distinct from the other.
The same difference prevails with respect to
astronomy; while the motions which the various
planets describe, are mechanical effects, the
cause of these motions is a physical one; while
the science of mathematics is the means by
which different distances and motions, numbers
and magnitudes, are measured and ascertainedj
the science of physics, on the contrary, is conversant
with the nature of the causes, by which
those motions are produced ; it explores the
essential properties of matter ; it distinguishes
the separate attributes of each ; it ascertains
the nature of the active, the aptitude and
capacity of the passive ; the power in the one
of overcomingthe resistance of the other; while
mathematics are merely conversant with effects,
physics, on the contrary, investigate the nature
of came. The causes of natural phenomena are
not to be discovered by mathematical rules, although
the effects may be ascertained by them.*
* I recollect to have seen it observed by some one, that if
any one were to attempt to prove by algebra, how it is that
fire burns ; to explain the nature and operation of the sun by
LAWS OF MOTION. 419
Had Sir I. Newton, confined himself to ascertain,
and to proclaim the effects o.nly that
take place in the planetary system ; there could
have been but one opinion respecting him, and
all must have bowed to that transcendent mathematical
knowledge which he possessed. But
when he attempted to account for the causes
of those effects, (of those motions,) by assuming
that the heavenly bodies were composed of
matter dense and solid, like the earthly matter
of our globe ; that attraction was an innate
force in matter, and that gravitation universally
prevailed ; I contend, that these assumptions on
trigonometry ; or assign the cause of vegetation, and of ratiocination,
from the theory of conic sections, he would deservedly
provoke the laughter, and incur the contempt of all ranks and
degrees of people ; and that he who attempts to guess at
causes, (and it can be called nothing else than guessing,)
merely from 4he appearance and superficies of things that
present themselves, and who makes the mistress wait upon the
handmaid, goes first to work with mathematics, and computes
by observation and experiment, the proportion of the motions
of bodies in particular cases ; and then infers, by deduction,
from what he sees, in such particular cases alone, the causes
of those motions which take place universally and generally.
He who does this, makes very great and fatal mistakes : besides
obstructing the path leading to the knowledge of the
particular fact, it prevents him from coming at any universal
truth. Judging in this way, is judging from effects only;
we see bodies moving, and therefore ought to conclude, that
they move themselves, by an inherent power they possess, or
else that the Deity is substantially present with them, and
moves them by his immediate influence.
420 LAWS OF MOTION.
which his philosophy is founded, were artificial
and unnatural; that although the conclusions
might be true, the principles from whenee these
conclusions were made, were erroneous in the
extreme.
Had the system of nature been considered
as it really is, a system of gradation, and of
difference, emanating from the great first and
universal cause, continued and ended in the
last species
1 of matter, we should not have
had to complain at this time, that bodies of different
species are supposed to be subservient
to one and the same law* that the matter of
fact is mivStaken, and confounded with the
law ; nor be called upon to ascribe to the
thing done (a mere effect) to be the cause and
the power by which these effects are accomplished,*
The difference, however* which exists between
the fact and the law, is as great as between
light and darkness. A law is a rule of
action ; a power, an agent ; by the energy of
which various effects are produced, according
to the rules which thai law prescribes. The
effects which are produced, do not constitute
* It has been well observed by Archdeacon PALEY, that
mechanism is not itself power ; mechanism without power,
can do nothing ; let a watch be contrived and constructed
ever so ingeniously, it cannot go \\ithout a spring, i. e. without
a force independent of, and ulterior to its mechanism.
XA\VS OF MOTION. 421
the law, they are the mere manifestations of
the power of the law. The voluntary muscles
of my body are made to move by the power of
my will ; the motion which is made to take
place, does not constitute the law, it is the
: accomplishment of the law, but is not the law
itself.
The laws which different societies, or nations
have established, for the moral government of
the whole, are rules of action which the individuals
are bound to obey ; the obedience of the
individual to those rules of action, is a proof
of the power of the law ; the power of the law
does not originate, but ends in the act of obedience
; the one is as separate from the other,
&s the power of my foot is separate and distinct
from the shoe which it moves ; as the hand
from the pen, and the pen from the paper ; the
paper constitutes the passive recipient of the
impressions which, through the medium of my
hand, it is made to receive, from my will, the
prime mover of the whole.*
The gradation which exisls in the common
*
Although it is very apparent that the thing done is not the
Jaw, but is the effect which is produced by the law, I am
somewhat surprised to find the late Archdeacon Paley, say,
” that it is a perversion of language to assign any law as the
efficient operative cause of any thing ;” and yet he very properly
declares ” that a law presupposes an agent, for it is
only the mode according to which an agent proceeds.”
422 LAWS OF MOTION.
matter of which the universe is composed, is
not more marked, than in the living beings by
which it is inhabited ; between those which
inhabit the earth only, and those which
are amphibious, of earth and of water, between
those that exist in water only, and
those that exist in water and in air together.
The gradual difference which exists in the
place of their abode, is as evident as in the
organisation and form of which they are severally
constituted; I shall select, by way of illustration,
a few of the organs in each. In the
organs of respiration, the gradation which
exists may easily be traced, from the simplicity
in the fabric of the common trachea, or air cell,
of the vegetable, to the branchiae, or gills, of
fish; from the branchiae, or gills, offish, to the
existence of branchiae and lungs, subsisting together,
in one and the same subject, as in the
syren, until we arrive at lungs only.
The difference may likewise be traced in the
construction of the lungs, from the most simple,
to those ofthe more complicated animals ; from
lungs which consist of large cells, with a small
absorbing surface, as in the amphibia, to the
higher order of animals, that possess lungs with
small cells, and a widely extended surface.
This gradation in the respiratory organs of
different beings, may be traced to the different
organs by which the blood is conveyed. In
LAWS OF MOTION. 423
vegetables, and in the more simple animals, the
blood of both is conveyed to the different parts
of the system, by vessels,whose difference seems
principally to consist in the nature of their form,
whether spiral or straight ; until the fabric of
this organ increases in power and complication,
from a crypta, or one single cavity only ; after
which it is found gradually to increase in its
complication, with additional power, by the aid
of a heart : iii fish the heart has two cavities ;
in the amphibia it has three, and in the mammalia
it has four.
If we were to trace the gradation which exists,
in that wonderful system, which distinguishes
the animal from the vegetable species,
and which is placed, (as PROFESSOR HARWOOD
elegantly expresses it,) “in the doubtful confines
of the material and spiritual worlds,” and more
especially in the attributes which flowfrom it, of
intellect and of soul; we should be compelled to
acknowledge, that the earth below, is connected,
with the heavens above, by different links
of one vast chain, which extends from the first
to the last of things, forming altogether one
perfect whole. We should conclude, that this
universal whole, is the work of a Divine Artificer,
who created it, in the best possible manner,
to answer the ends for which it was especially
designed ; that it is with a view to subserve
those ends, that we behold every particle of
454 LAWS OF MOTION.
matter which exists, possessing a natural and
inherent tendency, a vis insita, as it has been called,
to obey certain rules of rest, or of motion of
unity, or of union according to the particular
class to which it belongs ; by which it is made
to describe, under the same circumstances, the
same phenomena, by which solids fall to the
earth rivers flow into the ocean, by which
gaseous bodies expand and swell on the surface
of both, and are participated by the solar rays,
which warm and illuminate the whole.
It is through the efficacy of these rules, ; that
the planets with order and regularity move
through their allotted spheres,- the changes in
the seasons are formed, and tke divisions of time
established. These rules which have existed
from the moment of the creation, and which, it
is probable, will continue to exist until time
shall be no more, constitute the Laics ofNature,
or rather the instruments, or agents, which the
GOD OF NATURE employs in the physical government
of the material world.
THE END
