New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1852-12-28
Mechanics, Society Lectures.

Professor r. o. DOremus lectured before
the members Of this Society last evening at Me-
chanics Hall, No Az Broadway to a crowded house.
on the subject Of "The Atmosphere" of which
some Of its physical qualities were fret demon
strated. flask was exhausted by the air pump
poised balance. the air admitted and its weight
determined. The benefit accruing from this pres
alluded to, such as holding the bones In
opposition, aiding in respiration &c. The chemical
composition Of the cir stated to be about four hs
nitrogen gas, one-ffth oxygen and one part in two
thousand volumes carbonic acid each of these gases
were exhibited in succession and their chemical prop
critics demonstrated by experiment The lecturer
dwelt particularly on the composite character of
bonic acid gas, by burning carbon and oxygen, and
showed its formation by heating potassium in carbonc
acid carefully freed from water; the oxygen united
with the metal, forming potasse and black carbon
deposited in the tube.
The diamond burned in oxygen gas and car
bonic acid proved to be the result of the combustion
The results of the burning Of candle fame
smined, and water and carbonic acid were Obtained
Air expired from the lungs examined and the same
products were made evident by appropriate chemical
test He dwelt on the importance of this combustion
on the animal system for sustaining life that die
to live. The influence of sunlight the vegetable
creation, the decomposer of carbonic acid and the
evolver Of oxygen gas was alluded to, showing that
from this plants derive their carbon while the
time they berate the gas essential to animal
life, and thus upon the vegetable world animals depend
pot only for their food but for the very air they
breathe The speaker quoted the truthful yet po-
e,ic phrase Of his iilustrious preceptor CDR.
Drnper,) that THE atmosphere is the cradle
Of the vegetable but the coffin of the animal creation
One of the most remarkable results Of modern chem.
htry was succefuy attempted, viz. the solid6ca
ton Of carbonic acid 1t was obtained by the rapid
evaporation of the liquid carbonic acid contained in
strong iron receiver; on the principle that if
drop of the purest prussc acid be placed piece of
glass one half OF will evaporate while the remainder
sohdhes. On opening the receiver portion of car
bonic acid escaped as gas accompanied by shower,
Of a snow-lke substance-solid carbonic acid. me-
tals box was filled with the snowy substance several
times; the reduction of temperature was so great
that gloves had to be used In handling metals
brought in contact with it. Several pounds of mer
curry were frozen by being placed in mixture of solid
carbopc acid and ether the metal being cold "a 70
burn Some experiments were then made on what is
called the spheroida state Of matter platna cruel
bic was made red hot water thrown in il did not boil
solid carbonic acid left in its some minutes then
thrown out being still in solid state The crucble
wac raised to a white heat and the mixture OF solid
cArbonic acid and ether introduced; iron thimble
filed with mercury suspended in ii and almost In
santy frozen In contrast to the experiment OF metal
so cold as TO burn he exhibited too hot to burn,
by plunging bis hand into melted lead several times
and dipping out the fluid metal without injury The
iusots of lead mere melted before the audience by
blast lamps The explanation OF the phenomenon was
that the moisture the hand speedily converted into
yapor prevented the metal from coming in contact with
IT, From this experiment we can now believe the al
mcst incredible assertion. that men may walk barefoot
on mol On iron and not be burned.
The lecture was listened to and the experiments
watched with deep interest