Worcester daily spy. [volume] (Worcester [Mass.]) 1850-1888, 1859-12-30
Gitp ano Gountp ,antellioente.

Practical Lecture by Prof. SiIIfman.
The third lecture of the Mechanics Associ-
alton course was delivered last evening by
Prof Sillman, Jr., of New Haven. His sub.
ject was Combustion, Flame, and Fluid lamp
Explosion" He said he should endeavor TO
speak in very plain manner, on a very prac-
teal subject. He stated as a curious and in
teresting fact that in every community we find
many who are little acquainted with the laws
that govern familiar things with which they
have much to do, while possessing large
information on other less practical matters.
The loss of life by accidents resulting from
carelessness in the use of fluid is very great.
You can scarcely take up a newspaper but you
read of such accidents.
lie first spoke of the theory of combustion
and the nature Of fame, illustrating the sub
Ject by many novel and interesting expert
ments. Combustion is dependent upon the pre-
sence OF air. If we place any combustible
matter i'll close space it will cease to burn.
The phenomenon of combustion was illustrat-
ed In clear and interesting manner by various
experiments. He spoke of the wonderful law
OF nature by which two substances so widely
different as oxygen and nitrogen entered into
the constitution OF common air which is essen
thS ettuc Of0I llic SlODc, lilc COIllpO-
nent parts being always perfectly averaged.
The different properties and powers of the two
gases were clearly stated. Hydrogen gas
which is the lightest of all things and which
is the nearest to nothing of anything we have
was tested in various ways, its levity being
shown by introducing it in small balloon. 1t
Is different from oxygen in that as it will easily
burn, while oxygen will, in certain condi-
tons, consume anything else but itself Hy
drogen will burn only when in contact
with the air. 1t is a constituent ele
ment in burning fluid. Various expert
ments were given TO show how in certain
conditions the Introduction of flame in hydro
gen will cause violent explosions. Combustion
will always ensue when oxygen and hydrogen
or carbon come in contact. Gas is a mixture
of carbon and hydrogen
A very high temperature is necessary and
indispensable for combustion. Any cold TEN.
perature brought in contact with lighted
candle will extinguish it, because the tempera-
ture will be reduced by the cold faster than
the flame can produce the heat. Experiments
were given to show that flame cannot pene.
trate through wire gauze, a discovery made by
Sir Humphrey Davy, who constructed safety
lamp on that principle, the cooling effect Of the
wire forming a sure protection. Fluid cans
and lamps made on this principle ought to be
IN common use, to ensure safety from eXplo-
sons. Burning fluid in itself is not explosive,
and the lecturer had seen no well authenticated
case of explosion when it was properly used.
The accidents were the result of carelessness,
and the want Of presence Of mind to meet
them. When the fluid is spilled and ignited,
it is only necessary to throw wet cloth over
it, or to cover it with plate, or to let it burn
itself out. But most people, losing their
presence of mind, will try to eXtinguish it by
blowing it with the breath, or some other
foolish way.
The lecture was attentively listened to to its
close, and we have only briefly sketched the
prominent topics, the various experiments
forming its principal interest.