, 1874-02-21

| Va NA~AGy3
THE CONSERVATION OF ENERGY. By BALFous
| STEWART, LID, F. K. g., Professor Of Nature
Philosophy at the Owens College, M,nchestsr. New
! York: D. Appleton Co. Volume OF the Inter.
| national Scientific Series.
No discovery in Science has been moro prolific
| of results than the modern doctrine OF the Cor
| relation and Conservation Of Forces. Grove
| and Mayer, in 1872, first gave expression to the
| theory, that the different manifestations OF
| forces are mutually convertible; aud that force
in itself is indestructiblo and persistent. Joule,
I after An elaborate series Of experiments, estab-
| lished tho mechanical equivalent OF heat, and
reduced it to 1ts simplest term as unit Of work.
| Tynda1, in that most fascinating Of books OF
| Science, " Heat as Mode Of Notion" followed
/ it through its various trhnsfo7 o71nations, and
| wrung from flames aud liquids, iron and ice, the
smallest particles Of matter, and tho Sun him
| self, the secret Of their changes, and showed
them but the outward Visible appearances OF
matter acted upon and controlled By An imper-
ishable force. Nor has tho Investigation rested
here. 1feu early began to suspect that vitality
| itself WAS subject to this sa1no law; and that
| the growth and Development Of organic life, and
] all the thought and motion that constitute ndi-
| viduals aud societies. had their place under the
| same conditions that regulate the expansion Of
an iron bar, or raise water into steam under the
! application Of heat. Theories Of the possibility
OF q perpetual motion, no less than the sudden
acquisition Of material, social, and intellectual
prosperity through the enactment Of
laws, received doath-hlow when once
the fact was established that tho sum
Of forces is constant, and incapable
either Of creation or annihi1ation; and that rc-
suits are directly and inevitably related to tho
amount Of erertion or energy put forth, which
simply transfers tho abiding place OF so much
force from ono factor Of physical or social phe-
nomena to another.
Energy is power which the body possesses
OF overcoming resistance 1t is OF two varieti es ::
molecular or invisible energy, and mechanical or
visible energy. The first deals with the hack-
ward and forward motion which takes place
among the molecules OF body, without chang
ing its position in regard toeurrounding objects
tho last with the movement OF bodies aud organ
isms through space. Moreover, there is an en-
ergy Of motion and Al energy Of posstion,-as in
cannon-ball in actual motion, aud the game
ball at rest upon the top OF house. This dis
tinction holds for invisible molecular energy
truly % it does for that which, ia visible. En-
ergies may be conveniently classified as folIows
!. Energy OF visible motion,-as IN the planets.
q running stream. meteors, etc. z. ViBlble en-
ergy of position,-aB in head OF water, bow
strung for use, or clock wound up. Between
these is tho OF pendulum, which, in Vi
brating. alternately displays both modes. These
arc samples OF visible energies Tho following
are invisible, namely: l. Heat. 2. Molecular
separation 3. Chemical separation 4. Elec-
trical separation. S. Electricity which is con-
tnnous. q. Radiant energy which proceeds to
us from the sun.
Tho sum of these taken together is constant,
despite the continuous changes from one to the
other. The evidence upon which this assertion
ia based is pecuGar,-peculiar III itH magnitude,
in its universality, in the subtle nature OF the
agents with which it deals. It cannot be proved
as we prove tho conservation of matter in chem
ical experiments, but, under certain test condi-
tions, We obtain results which prove the Law to
be true in all cases where rigorous experiment il
available, All work can be changed into heat,
but. although heat can bo changed back into
work, oil OF the heat cannot be utilized. Beyond
what is sQuandeted ia the shape OF friction,
Bome escapes into space, and leaves tho earth
altogether We caunot prevent its going, rad,
with reference to the earth, cannot say that the
8um is constant But the physicist, in unfold
ing the laas of Nature, stops not At the earth On
which VIC live. Gravitatiou holds it's sway in the
furthest regions of space, aud hero We ind our
energy which is dissipatcd. We may, indeed
assume that, for all the energy radiated into
space, an equal quantity returns to US IN energy
radlated from the sidereal system. But, putting
thia aaide the main source Of cur planetary
energy is the sun. 1t is stored in the shape OF
fuel, food, head Of water. tides, and tho ener-
s. OF chemical separation in native sulphur,
iron, etc. besides which, there il tire energy OF
air aud Eater ia motion.
Consciously aud unconsciously, this energy
ia gradually becoming transformed into beauty,
and some proportion OF it is beyond cur power
to retransform. Hence the startling conclusion
that more aud mora will the mechanical eucrgY
OF the universe be transformed into univer-
sa}ly-dlnused heat. until it will no longer be aft
abode for human beings since the production OF
work md the possibility OF life depend upon df-
ferencea OF temperature. Although, therefore,
servatiou OF energy, yet, as regards usefulness
or fituess for living beings, the energy Of the |
universe is in process of deterioration.
Il is not within the province ct Prof Stewart |
to deal with the application of these principles |
to other than inauimate matter, but in an appcn-
dix are added two essays: on the "Corrclation |
OF Vital with Chemical and Physical Forces "by |
Prot. Joseph Le Coute; and the aCorrelation |
Of Nervous and Mental Forces" by Prof. Alex !
aodes Balm; which will give tho reader an idoa
OF the relations OF energy to lifo.
This work very opportunely. follows that OF
Prof. Cooke upon the "New Chemistry" and
may be read in connection with it to great nd |
vantage The two combined cannot fail to pre- |
of chemical aud physical science It is possible,
with reference to the work Of Prof. Stewart, that
some faint tinge Of disappointment may he felt
By those persons who arc familiar with the more
advanced anu prot0undef treatment OF the 8ub- |
ject by Grove, T5ndail Heimholtz, Spencer, aud |
others; but, bearing III mind the purpose Of the |
works forming the International Series the vol !
ume will ba found admirably adapted to the t
wants OF those who desire plain statement Of |
the theory, unin-umbered with technical and |
minute details.
4 Novel by Rhoda Broughton.
NANCY: NOVEL. BY RHoDA DnouGuTos, Author Of
"Good-Bye, 6weethea1t," etc. New Iozk: D. Ap-
pleton Co,
This is in the first half Of it, altogether the !
raciest book ne have read in long while. It
has much Of the spicy flavor of Miss Alcott'a
. Little Women" andrecalls that charming story
BY numerous points Of resemblance. Miss
Bsoughton does not prosper we'll in the concep-
ton Of plot, and her characters are apt to be
Inconsistent. but sbe has Al extraordinary fac
1ltv for sustaining colloquy and, as there is
lothing in all tho world more fascinating than
,risp, witty conversation. abe keeps her readers
amused by the exercise Of this talent.
sho manages clima1es, too, clever1yi and near
cLs s,,+o r;odo |