the latter case a few grains only lying near the primer would be
ignited, and these would soon become extinguished by sudden release of
pressure bringing about a cooling effect due to expansion of the gases.
In small cartridges a large fulminating cap is all that is required, but
in large cartridges it is necessary to resort to additional means of
ignition.

In France, where experiments were conducted with a 37 millimeter Maxim
gun, it was found to be impracticable to use a fulminating cap
sufficiently large to ignite the powder and cause it to burn. Therefore,
a small ignition charge of black powder was employed, it being put in a
capsule or bag and placed next the primer. On firing at the rate of 300
rounds per minute, the black powder, though small in quantity, produced
a cloud of smoke through which it was quite impossible to see. The
inventor of the gun then prepared for the French some wafers of
pyroxyline canvas, which were placed next to the primer, securing
thereby prompt ignition without the production of any smoke.

Smokeless powder, made as I have described, cannot be detonated by a
fulminating cap of any size or by any means whatever. A large charge of
fulminate of mercury placed inside the cartridge case next the primer
will not detonate the powder, it serving only to ignite it and cause it
to explode. But even this would not cause the powder to explode except
it be confined behind a projectile, that sufficient pressure may be run
up to make it burn in its own gases.

Some curious experiments with smokeless powder may be tried with a shot
gun. If the fulminating cap be large, the powder fine, the wads numerous
and hard and the charge of shot heavy, all being well rammed down, and
the paper case well spun over the last pasteboard wad, a charge of