worked by a lever. Round
the upper edge of the cylinder is fastened a canvas bag, into which the
powdery dynamite is placed by means of a wooden scoop, and the descending
piston forces the dynamite down the cylinder and out of the open end,
where the compressed dynamite can be broken off at convenient lengths. The
whole machine should be made of gun-metal, and should be upright against
the wall of the building. The two girls, who sit at tables placed on each
side of the press, wrap the cartridges in parchment paper. From these huts
the cartridges are collected by boys every ten minutes or a quarter of an
hour, and taken to the packing room, where they are packed in 5-lb.
cardboard boxes, which are then further packed in deal boxes lined with
indiarubber, and fastened down air tight. The wooden lids are then nailed
down with brass or zinc nails, and a label pasted on the outside giving
the weight and description of the contents. The boxes should then be
removed to the magazines. It is well to take a certain number of
cartridges from the packing house at different times during the day, say
three or four samples, and to test them by the heat test. A sample cut
from a cartridge, about 1 inch long, should be placed under a glass shade,
together with water (a large desiccator, in fact), and left for some days.
A good dynamite should not, under these conditions, show any signs of
exudation, even after weeks.[A]

[Footnote A: For analysis of dynamite, see chapter on "Analysis," and
author's article in _Chem. News_, 23rd September 1892.]

~Properties of Kieselguhr Dynamite.~--One cubic foot of dynamite weighs 76
lbs. 4 oz. The specific gravity of 75 per cent. dynamite is, however,
1.50. It is a red or grey colour, and rather greasy to the touch. It is
much less sensitive to shock than nitro-glycerine, but explodes
occasionally with the shock of a rifle bullet, or when struck. The
addition of a few per cent. of camphor will considerably diminish its
explosive qualities to such an extent that it can be made non-explosive
except to a very strong fulminate detonator. The direct contact of water
disintegrates dynamite, separating the nitro-glycerine, hence great
caution is necessary in using it in wet places. It freezes at about 40 deg.
Fahr. (4 deg. C.), and remains frozen at temperatures considerably exceeding
that point. When frozen, it is comparatively useless as an explosive
agent, and must be thawed with care. This is best don