San Marcos free press. [volume] (San Marcos, Tex.) 1877-1892, 1882-08-17
GUN.COrTON.
The power OF the Terrible and Dangerous Ia.
plosiye.
DR., Doremus. in the New York sun

piosive.
Dr. Doremus. In the New York sun.
In response to Supt. Walinq.s criti-
cism, allow me to state few facts con-
corning explosives. which / shall be
happy to demonstrate to him, II he will
honor me with his presence at the Col
lese of tho City If New York, or at
Bellevue Medicil College. II gunpow-
der is placed in basket made of coiled
platinum wire and is then inserted in O
glass jar arranged so that 10 can be ex
hausted of air byan air pump, on apply
ing current of electricity to the coil,
SO as to render the wire red hot. the
gunpowder will neither explode nor bm n
with flash. 1t will apparently boil,
with purple light, and will require
from five to twenty seconds for its COM
plete combustion, depending on the
quantity of powder and the amount OF
air removed.
All know that gunpowder has its own
supply OF oxygen-it do IS not require
any from the air; for We shut out the air
when we load pistol, rifle or can
non. The nitrate OF potash furnishes
the oxygen for the carbon and sulphur
of the powder. The cause of the tardy
combustion of the gunpowder in the
exhausted receiver is the diminished
pressure.
But wrap the powder in paper, and
we have the firecIacksr; inclose the
powder in an iron sphere, and we have
the bomb-shell. As the powder burns
under increased pressure produced by
its own gases, it explodes with in
creased force. An ounce, or even o
pound of powder, when burnt in tie
open air, produces no explosive sound
mere ly q pull.
The iulmi mates of silver and mercury
which are used in percussion caps will
also burn slowly when placed in the
platinum coil referred to al heated red
hot after the air has been exhausted
from the glass jar. Yet in the open air,
when fred, they will explode with a
sharp sound.
If o lock of gun. cotton(of the most
explo ive kindD, say foot in length, be
suspe lded in glass jar with said plat
mum coil, and, after removing the pres
sure of the air by pump, if the coil is
made red hot by an electric current,
the gun.powder will not explode, nor
will fame or spark of fire be seen;
the eun.cotton will gradually disap-
pear.
Even under the pressure OF the air,
or, in other words, in the open air,
small quantities OF gun cotton of the
most explosive variety when lighted do
not explode: they merely burn with
bright fash of light. When we pre-
pare gun-cotton before class III chem
istry we frequently place lock OF 1t on
students hand and fire it to show how
quickly it burns; for he scarcely feels
it. This is one OF the trivial tests OF It's
good quality. Another is to place the
gun. cotton on gunpowder, then apply
light. If it fails to ignite the powder
it is the explosive variety; if it set fire
to the powder it is inferior in character.
PHOTOGRAPHERS gun.ootton, which is
soluh le. in alcohol and ether, and is
use for making collodion. will burn
slower. If placed on gunpowder it will
ignite it. 2.
inclose the explosive variety of gum
cotton in a stout receptacle. Now fire
it. and it will exhibit three times the
force of gunpowder.
| If Superintendent Walling will fill a
teaspoon with nitro glycerine and apply
to it lighted match, he will find that
the nitro glycorine will quietly and
slowly burn, with green-colored flame,
because it is only subjected to the press.
of the air. But if he places this
amount of nitro-glycerine in a closed
vessel and fires it, would advise him
to remain at respectful distance from
it.
I have placed fluid ounce of nitro
glyc crime in a metal cup, connected with
one pole of galvanic battery, and, on
applying the opposite pole of the bat
terry to said liquid, / haye shown before
@ medical class that the nitro-gly cerine
burns tardily and without noise. With
said battery 1 had previously fused
a Id volatilized platinum, iridium and
other refractory metals to demonstrate
the intensity OF the heat. Yet, il q
single drop of nitro glycerine ID placed
on O smooth surface and struck bud
den blow the explosion is stunning to
the ear. The same Law applies to
giant powder, dynamite, rend.rock and
other terrific explosives. They must
have pressure to exhibit their power.
They burn quietly and slowly without
il.
The biggest cavern is the Mammoth