, 1876-11-04
(COntiNnel trOm setDnA pa9sl

some other form Of force, and that in the
proportion that is the precise equivalent
of the amount of heat first used. When
coal is dcCulLposrd by fire in the furnace
OF IA steam engine, it gives ont exactly
the amount Of heat and light that it
absorbed from the sun, perhaps millions
of years ago; this heat, transferred to
water, is there converted into motion,
which, hy means Of machinery is madc
subservicut TO the purposes Of man.
Like the gcni OF an oricnta! tale, it be-
comes Il faithful slave rs long as the tai
isn,nn that commands its service is used
Alright; though slight mistake in the
mode of its suhiugation may become ia
tal to him vino wOuld use its sOrccry
OF course it cannot he expected that |
can go very fully into the details of this
recOndte and complicated theme in the
narrow limits Of single lecture; but
what | have said on the subject -of ma
chincry and plants may furnish some clue
to the understanding of the more com
plcuted notifications Of force that take
place in a living organism. An animal
is simply n machine OF more perfect
structure than any that can be tabrica-
ted by the haud OF man. AS Rumtord
sagNciously remarked, the power of an
animal is due to its food, as the power of
steam engine is due to its fuel. Both
animals and steam engines are arrange
ments OF parts adapted to put the forces
that are developed by the chemical de-
compositions OF the food or the fuel into
II working state; but all artificial means
perform their work very imperfectly, be.
cause by far the greater part Of the heat
of com buston is lost, carried off by the
convection Of surrounding bodies, or
TadOted into space.
Whenever the motion Of body
through spacc is checked, that notion
is by no means destroyed, it Is merely
transferred into vibmtory motion
among the molecules of that body, which
is manifested in its heat. This vibratory
or shiycring motion among the particles
may be so intense as to break down the
solid structure OF that body and make it
flow, or 1t may go still farther, and dis
sipate il into vapor. When we consider
how the percussion of the finger on the
key of piano may be converted into the
vibrations of a musical string, we shall
have less difficulty, probably, in conceiv-
ing how the motion of the mass may be
converted into motion of the MOLE
cules. Force and matter are equally in
destruCtible; they can neither be added
to nor subtracted from; both are eternal
and immutable in quantity; though in
shape aud quality they are undergoing
incessant changes. These changes con
stitute the life of the universe, and they
are all under the control of the ono great
aad presiding Force or POrer. To this
one and omnipotent Force, in one or
more of the infinite modes of its action,
are to be attributed all that can be seen
or thought of in the changes that are
continually going on in the material
universe. Whilst this power is 50 vast
rs to pcrvade and control the boundless
universe, it is ut the same time SO minute
and searching in its operations rs to con-
stitute every motion or affection OF the
smallest particle Of matter. TO be sure
we may, if we please, suppose another
controlling force outside of this, and su'
perior to it, and still another, and so on
al iHfnitum, after the manner OF the
most enlightened Hindoo philosophy,
that makes the earth revolve on the tip
ola cows horn, the SAID COW standing
on the back OF a turtle, the turtle stand
ing on rock, and the rock on--God
knows what But unfortunately, OF
rather fortunately in these cases we m'lst
stay somewhere, and perhaps the safest
plan Is to stop where the laws of nature
leave us. 1t is laid down as Oil axiom in
natural philosophy, that in seeking for
the causes of phenomena, we should rest
contcnted when we have found sufficient
TO explain them satisfactorily, lest We
become bewildered in labyrinth of di
vergent theories.
These spcculatious may be thought tc