, 1870-08-28
The Conservation Of Energy.

rum Nature
We eha1i Eow proceed to trace tho prog.oss
Of crcEgy through honc OF ita most important |
tzanst ornztioass. To begin with, that ons 10 |
which ne have airead; alluded, What Gecoues |
of the enesgy Of falling body after it strikes |
the eatth:, This question may be varied in > !
g1eat nunber OF ways. We may ask+ for iu-
way train when it is ator,scd7 what becomes
Of tho energy Ct ! hara.ner after It has struck
the any,l7 OF cannon ball after it has struck
the target? and so on
In ali tl,eso varieties We zoe that either per-
cussldn or friction il at work; thSt it is frie-
tiou that stops railway train. anu it is per-
c,lsaloll thai etsp}'4 this motion Of q falling
stone or Of failing hammer. 20 that our qu:n-
ton is, il, reality, MIA, becou,as OF the energy
OF Visible nao.ieu When 1t las been stopped by
percussion or friction:
EumfeS1 e:ll nGxy were the pioneers in re-
plying to t}ie important question Run,fori
| founl that in the process Of lsring csut.on
tho heat general c.1 wiz soElrtiuaes 80 EEeat al
! 10 boil Ha IT, aud he supposed that Work Was
| changed into heat in the I,rost.s Ut boring,
Dary again melted TWO pieces OF ice by caus-
! Ing them to rub asyai1,rt esch other. aud Le
likewise concluded that tho work spent Oh
tliis ltzeccss lsai bceu converted into hest.
Ne see nov why Ag hsmmsnns c<'in on an
anvil NE can heat ii worry greatly, OF why, On
dark night tue sparks are ecen to i!y out from
| tic trcak-wEetl which stc.s tho motion Of the
rni1way trim, or nhy hy inhbing metal but
| ten Violently backwards and forwards against
= piece Of wood We can render II so hot Is to
scoreh our hand, for iu all these ca.es it il the
energy Of sixible n.otiun which is being con-
| vrrtel into hest.
D7t, although this *ss known nezrls cen-
tuIy ako, it was reserved for Jou1e, an Eng
lish philosopher OF tho present day, to point
out tue numerical relation subsis,ing between
list species Of energy which we call visible
emotion, aud that whicl. VIC call hest
The result Of his numerous and laborions
! ea1 ,e1in,ents sss. ilAt il n pound Of wAter be
| dropped from height OF 10 feet, under the
in:lncucc Of gravity, and If the velocity which
il attsins ho suddenly stopped and converted
tie whole mass degree Fahrenheit in tenn
l4rAturc. -.-....
Frnn This, he concluded that, when ponnd
Of water is heated degree Fahrenheit in
e.,erly enters ,rso the waie1 which is e,lu,sa-
ltet to ~ toot-roulde, that is to sag, to one
pound 1ai.ed ~ feet high against the inlu-
eI es OF. gravity. " allowed to fall ~ feet
] under the taule influence.
lie found again That i! pound Of water
were to twice fall this distance, or 1,5i4 feet
under Sra,ity, the velocity il stopped would
] r..st. its Temperature 2 deg. Fahr-. and, in
fact the Ese IN temperature nndur such cir
e'm.tsrces is proportional to tho height from
| which The pound Of watcr il supposed to fall.
| l;y this means an exact relation is established
b.twecn hcat aud work Grove Wis the first
! 10 point cut this pt.'batility OF 3 connection
between the various species Of molecular
e:.esgE: and the researraes Of Joule, Thon1-
| scn, and otLers, have established these rcla-
tirns With numencal ACCURACY. No better OK
ample ol tie correlasicu Ut tie yarions kinds
OF ercrsy can br given than uL:l takes plaee
IL EslvAuic battery Let us suppose that
zilc in TIC 1actal used. Hero tho soarcc OF
energy Is the burning or chemical conbiaa'
tion Of the zinc with oxygen, kc., in order IA
I f,r11y a 1Hf} ~
il in fact much the same - wlen coal ,e
1.1raed; 1t is the energy produced By chenni.
c=l combination. Now, as we-h.yc said. the
zinc combines .:Ln the oxygen, anu suIPh.te
OF zinc ID produced, but tho result OF thls
! continuation does not at first exhibit itsnlf it
the form OF heat. hut rather in that Of n
! electric current. No doubt great portion q
| the energy OF This electric current is ultimate
! II spent in heat, but We may, II We choose
spend part in promoting chemical deconpohi
. 1h this case, part or tho energy Of tho battery
| derived an has been stated, from tho brvninI
: Of the zinc, is spent in heat and part in de
: composing the water, and hence NO shall nav
!. = compose Eut II, when VIC have decompose
4 tI,e water, We mix together the two gases
6 hydrogen and oxygen. which arc tho II
: +uI.s OF this deaam7oaition, aud expIodetaem
L VIC .han recover tire precise .dca:icucy Q
. heat. Without the decomposition, 1st US -
. that the burning in the battery Of 4 cettai
= weight Of zinc gives rs heat cqul 70 100: bu
with the decomposition only 50, 20 units Q
: energy have therefore become spent in u
q aecompositiouf hut II VIC explode tho mi,
o tusn OF gases procured from tho decompoe
e ton, We shall ret back hcst equal to 20, an
T. thus make the whole reenlt Of tho burning
!. The zinc 100 nn3ts Of energy, as before.
d In like manner, II our electric battery
Ii made TO do work, thus forming kind Of CT
Sine, We shan bare tho heat prcducod h5 II
@n1<fN hal t1@-Yt
as The mech.n,cx cHecf which We haTe ohtsine
To- from this engine.
4 There Ia nothing for nothing in tho unirers
IS <eaerS. 3. S1.TaRz.