New-York tribune. [volume] (New-York [N.Y.]) 1841-1842, 1841-12-28

-
about to plunge mo II. fe; If a thermometer be
first suspended in the air, ana then plunged into the
water the same temperature will be exhibited 10
both cases. What, then makes the difference IN
the sensations! his Is ea,lly exPicaNle uper ;he
principles have bseu cousidruns Il j. uu- ina.
hquids ere not good ict4rs Ji neat ia tie s-ric,
sense OF the term ls.r, ,arlte il different way
Ii a person plunge Ia-. water nc temporal re Of
which Is lower taan la, Of ihe air. The Particles
which FRS; touch Ii. body become warmer, and.
by a wcll-Anown law, rise Immediately to Jne
surface. flesh stream OF cold particles rIshes 20
bis BODY which in their turn rise gad give place 20
others. Thus there j. kept 10 d Constant stream
# cold particle. toward lis body. which clearly
accounts tor the apparent temperance. AR may
be heated 70 the temperature OF boring water and
iii a person may remain in II without neon
,enience, wnen, If he plunged into water OF the
sane temperature. he would be immediately
scalded. These observations clearly account for
tie exhibition OF feat IN England, and, f,r aught
know in this country. OF one NJ. Chabert,
famous tor exposing himself TO g degree OF heat
which it was thought would destroy any other
person. He had IA oven winch hs va, accus-
toned to have heated to such degree that he
could broil beet steak By is heat. while he
quietly slt in the oven and cooked and ate ms
steak. But Chaoert did not stand upon the
bottom Of the oven: nc took care 10 have beiw cen
ais feet and the iron which formed is bottom aud
on which the steak was cooked. some non-condgct-
ing substance. AK not beng good conductor
and by being careful to have Il carpet or piece OF
cork upon which Ia stand Ae could quietly remain
in the oven without ini1y. 30 lha, these teats
we're nothing mole than an experiment on the
principle Of corduStor, and noNcoaduc;ors. You
-,
ances are accounted Tor by the simplest scientific
principles
The same man pretended 10 swallow PrIs-ic
Acid Now there are certain liquids which no one
ever swallowed without swallowing a portion OF
This Acid-which may be taken in ysiy small
quantities with impuniiy. Chabert', leats in Lon
don were stopped very suddenly by gentleman
who brought 10 the Concert bo,ll- OF real prls.ic
acid, and proposed to the iugsief that he should
swallow IT, which, however, he veiy p'udentiy de-
cined to go.
The principle Of the non-conduction Of beat i
illustrated by the economy .. .tcaul-boers in Eag-
and where it Is q great object Ia produce inuc-
steam as possible with the least possible expense
Of fuel In Cornwall not.iug Is more striking than,
in hot weather, to walk into. the boiler-room and
ind it the coolest place to be found. Tho boiler
in this case is surrounded by the best nOn-conductor
to be found and the material which l. found to
answer the purpose i saw-d1st. The Cornish
boilers, which are used at a temperature as high
IS those OF any Of your high-Ptes,ure engines,
coated with three or four inches of ,aw-dust. TN.
non-conductor prevents the escape OF the steam
and all that is evolved by combustion is kept within
the boiler and the is kept cool any
need be. have alluded to the fact that flannel
IS frequently used in warm climates as q defence
hoo, klo,,ly,,. Lac.
upon the same principle, put around stcam-bocrs
before The superiority OF saw dust known. Ice,
which understand is conveyed from Boston to Ia
dia, is also wrapped in blankets this is nothing
more than an illustration of the principle | have
endcavorcd to devclope
All the impressions OF the senses require 10 be
interpreted by the understanding and tins bringsus
back to the truth that the Creator who has given
he intellect, intended that We should use and apply
tito all the phenomena of the which give such
talacious testimony. We are accustomed TO rely
on the evidence OF the eye with the most implicit
confidence; AID Yet there is no one OF the senses
whose testimony is so faacious as chat Of this
same eve, all-periect as it Is in mechanism. The
impressions made upon the eye, when carefully and
examined, are extremely curious.
Nith the structure and arrangement OF this organ
you are all doubtless familiar. Light is Il
Ieral substance; it was. however, long supposed
and is still held by many that this is. It's nature;
but according to modern discoveries it is only
caused by the undulations vibration, o the me-
dunn through which it passes. The best way, per
maps, of calculating this point is from the analogy
of sound, as the same laws which govern The one
govern the other also Noone supposes that sound
i, material substance you are all aware that lis
merely The effect oil system o! pulsations produced
IN the atmosphere and propogaied through that
from the body struck to the Now ii you only
admit the existence in nature OF fluid, infinitely
lighter, more uttenuaed, elastic, and delicate than
the air, pervadins the whole universe and that u-
cierous body capable acting upon 1t in the same
way Us Il sonorous body upon the arr there will BE-
no difficulty in concevinc il to be system OF pull
satons transmitted through the fluid, infinitely more
delicate and rapid than those Of sound. This Illus
traticn conveys the best notion ! AIN capable OF
giving, of the modern theory of light The Sun or
lamp acting on this uiher, 1t Is called, puts it
into state Of pulsation; the vibrations passing
through it rs those of sound throush the air. This
pulsatioa Is propagatcd to the eyc-reacaes the
rc,ina and puts that delicate membrane into state
OF tremulous motion which is the proXmate cause
OF the impression OF light rrodGced in the mind.
1t has keen, moreover, discovered by modern SCI
that the varying rapdity OF these vibrations Is
the OF The difference in the ceors Oi the spec
nun and what IS sill more remarkable, these VI
btutiens have been subjected To admen,urcmeul
The various colors, blue, green, Nc. are nothing
rssre than the effects OF the different rates OF pull
sation impaired to the reuna a The back Of the
eyc-ball. a ray OF vib alton enters the chamber OF
the eye through the puPi-a small black spot in
the centre of every eve, which /. merely aper
ture through which roo might be thfust-and
causes the relina to vibreie al different Sci
ence has discoyereda method Of computing the rate
at which this membrane puisates and the number
Of VIBRATIONS per second, when the sensation OF red
ness Is produced and SO for the other colors. There
would be nothing extraordinary in this II TINS wa.