The Chemistry of Powder and Explosives - Sciencemadness Dot Org

214 NITRIC ESTERS
fessed he had neglected to examine the thermometer, made
his fire under the boiler, and gone to bed. . . . Fortunately,
this accident involved no damage to life or limb, whilst a
very instructive lesson was taught in the following circumstance:
Within twelve feet of the magazine was a shed, sixteen
feet by eight, containing twelve fifty-pound cans of
congealed nitroglycerine ready for shipment. This shed was
utterly destroyed, the floor blasted to splinters, the joists
rent to fragments, the cans of congealed nitroglycerine driven
into the ground, the tin of which they were composed perforated,
contorted, battered, and portions of tin and nitroglycerine
sliced off but not exploded. Now, this fact proves one
of two things: Either that the tri-nitroglycerine made by
the Mowbray process, differs from the German nitroglycerine
in its properties, or the statements printed in the foreign
journals, as quoted again and again, that nitroglycerine,
when congealed, is more dangerous than when in the fluid
state, are erroneous. 30
Mowbray used his nitroglycerin in the liquid state, either
loaded in cylindrical tin cannisters or cartridges, or poured
directly into the bore hole, and exploded it by means of electric
detonators. The electric detonators were operated by means of a
static electric machine which caused a spark to pass between
points of insulated wire; the spark set fire to a priming mixture
made from copper sulfide, copper phosphide, and potassium
chlorate; and this fired the detonating charge of 20 grains of
mercury fulminate contained in a copper capsule, the whole
being waterproofed with asphaltum varnish and insulated electrically
with gutta-percha. The devices were so sensitive that they
could be exploded by the static electricity which accumulated on
the body of a miner operating a compressed air drill, and they
required corresponding precautions in their use.
Liquid nitroglycerin is still used as an explosive to a limited
extent, particularly in the blasting of oil wells, but its principal
use is in the manufacture of dynamite and of the propellants,
ballistite and cordite.
Dinitroglycerin (Glyceryl dinitrate)
Dinitroglycerin docs not differ greatly from nitroglycerin in
its explosive properties. It is appreciably soluble in water, and
more expensive and more difficult to manufacture than nitrogly-
pp. 44-45.