The Chemistry of Powder and Explosives - Sciencemadness Dot Org

106 PYROTECHNICS
of caps which are dried, packaged, and sold for use in toy repeating
pistols. Or they are cut in squares, one cap each, which
are not dried but are used while still moist for making Japanese
torpedoes (see below). The calcium carbonate in this mixture is
an anti-acid, which prevents it from deteriorating under the
influence of moisture during the rather long time which elapses,
especially in the manufacture of torpedoes, before it becomes
fully dry.
Mixtures of potassium chlorate and red phosphorus explode
from shock and from fire. They do not burn in an orderly fashion
as do black powder and most other pyrotechnic mixtures. No
scrap or waste ought ever to be allowed to accumulate in the
building where caps are made; it ought to be removed hourly,
whether moist or not, and taken to a distance and thrown upon
a fire which is burning actively,
Silver Torpedoes
These contain silver fulminate, a substance which is as sensitive
as the red phosphorus and chlorate mixture mentioned above,
but which, however, is somewhat more predictable. They are
made by the use of a torpedo board, that is, a board, say %
inch thick, through which %-inch holes have been bored. A
2-inch square of tissue paper is placed over each hole and
punched into the hole to form a paper cup. A second board of
the same thickness, the gravel board, has ^-inch holes, bored
not quite through it, in number and position corresponding to
the holes in the torpedo board. Fine gravel, free from dust, is
poured upon it; the holes are rilled, and the excess removed.
The torpedo board, filled with paper cups, is inverted and set
down upon the gravel board, the holes matching one another.
Then the two boards, held firmly together, are turned over and
set down upon the bench. The gravel falls down into the paper
cups, and the gravel board is removed. A small amount of silver
fulminate is now put, on top of the gravel, into each of the paper
cups. This is a dangerous operation, for the act of picking up
some of the fulminate with a scoop may cause the whole of it
to explode. The explosion will be accompanied by a loud noise,
by a flash of light, and by a tremendous local disturbance damaging
to whatever is in the immediate neighborhood of the ful-