, 1874-03-20

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PROF. PEPPER.
The Theory nnd Frncttco Of 0rtlca.
It must be evident to tho most casual observer
that nhilo to standard drama ia appareptly
growing 1caa and tesa nonn1nr IN nh,caro and
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~ ia''' 'aAouenou' t1'o oa'so" o'"So' - nos
oocauao thero Is 4 laok OF audiences WHO demand
8omething higher than mora spectacle And blood
aud thuudor. Without stopping to DISCUSS tho
:. ~" .".'" . s' .Ao T.. a'o'oano ~ A.,
Nv wv oens oi"1n"t'o petAola'a1oes' ~ 1t "o1tn
noticing that scientific subjects arc very "tak-
Ing" in tho lecturc-ield, and TINT the
audiences arc composed of tho most
,rI,;,oto1 ,oor,, t., a. .o,,,,t. mi. t,I....
~ J .o uao ,1s' peon
so!S nosieeaoio IL tAo I"at "nolo nuAey' Ayn-
dali, Pepper, aud Proctor have drawn crowded
houaeB for several successive nights. but IL was
feared that tho West would bardiv natron,zo The
.xno,o,,s ~ tha ohatr.,t .a;oa.o. -. ..,, ~
uApouonto " WV oes1"o1 osono'n ao "ei'. .to1'
fTootor, IN gteat measure. alspelled shis ldea,
drawing one of tho largest loctaro audiences
ever soen hore. As some OF tho principal at
fractions uf tho lecture consisted Of lllustra-
tions which could not DO we'll soeu from the OK
tleme cdgea Of tho nall, it was not to DO expect
cd tlat such largo auditorium III TINT or Lilo
11cCorm,ck hluBlu Hail should bo entirely Tiled,
but the empty seats Were few, and only On tho
outsiue Of tho hall.
Prof. Pepper began his lecture at a few min
osF oii s soeon 1' se ss t % ao aa arya
Who nofe then Walking abonts making 30 much
noMe as to provent tue lot.urcr from being
heard III nj parts of the ha.l.
The lecture may be.sa.d to have consisted Of
two departments, s,-theorettcal oxposl;ionB mud
practical Illustrations. Wnlle tue latter wore
probably the most interesting to tho general OBJ
Beryer, tAere WAS enough instruction III tho pure
" theoretical part uf tno lecture tn no vary ut
RE n n
PROT, Pepper Logan by saying that It had quite
Burprsed hun 90 hee WHAT Largo audiences hau
assembled in every place in tins country to lts-
ton to Lectures upon purely scientific subjects
Altar iurthor cohlpliMentloG tno AMERICAN peo"
pie, 10 went ou % epeaR OF tho particular
branch Or the scientific research IN Which ho WAS
engaged. ...-....-.
III THO hrst piaco. tho qnostlon rcourrea: What
WAS l1shtI Ne Knew tnae thcrc were three
sources oi light nlht Tue ll4ht OF tue sun anu
other inie.ensly.lamlnonb heavenly bodies,
which might bo CALICO co6mlcal 4isht seeohdt
tile Light produced ny the cohDustlon Or matter
On the oarth, Known aa terrestrial Aght and,
third, fotlecsea or olilnsoa ngnt, "lthoat walch
the sun would appear Ako brtght electric !iglt
in dark chaam. Thero Woiu DO ono brilliant,
burning glow III tile direction OF the BLU, or my
other luminous ooay, anu everywhere elhe
would be darkness.
deal aeous TIC sun, put they could not toll US
WHENCE it derived its heat; None OF the theories
would stand all tests: All thas no could learn
OF the constituents OF The great mass was taught
by aual,sls Of its rays. The spectrum showed
ua tho character OF tho flames; whether they
were composed Of hydrogen or other metals. aud
wlnt the metals were, but the rca supply Of fuel
and CONSEQUENT ca1se Of heat could not DO de-
ter1niuod With regard to toe light OF tile sun.
however, something more WAS known.
The lecturer then went OH to explain the de-
ge!opmout Of tho theories Of light from the
corpuscle theory Of Newton to tho present &c.
copied ono OF tho vibrations Of PARTICLES of
ether, which il supposed to penetrate and exist
in everything.
1n tho Illustration Of the character of light,
experiments. First, tho hui having been co,ll-
pletoly darkoncd, to illustrate tho light Of the
sun, which was caused by the combination Of
| metals, tile Aamo Of uu oxy~hydrogen blow-pipo
MAS turned upon a small mass Of soft iron. In
short time tho iron was in molten state, and by
forcing tho tlamo down into tho scothing mnss, it
was caused to toil over, or rather largo elobuios
in their incanlescout condition woro thrown into
the air aud very brilliant pyrotcchnical display
was tho result, similar 10 TIM; produced in
mould.
| Next lie showed how terrestrial light waB pro-
d,,ced by lighting q torch OF some c1rbonacoo,ts
materia which he said was type ofall terrestrial
| Flames. As long as the t|ro could obtain only so
much oxygen from tie air, It would be duh and
tie oxygen VIVA admitted or forced
| into tho 1laine in creator quantities. As al H.
lustration. tic aasistaut waved the torch quick
~, making immonao tlamos, similar to ihoso
beautiful OF the evening. It showed how light
conJ bo maio TO diff.,So itsolf through a,1y
medium wlisL would pernit yibratiau Of tLe
light through itB particles, Ho first passed q
ray from the oxyliydrogcn light through water