hot wire is more rapid in action. The ignition temperature may be
somewhere in the region of 180 deg. C.

All the members of this class of explosive when kept for some time at
(for them) moderately high temperatures, such as the boiling-point of
water (100 deg. C.), show signs of decomposition; oxides of nitrogen are
liberated, and some complex oxidation processes are started. Carefully
prepared gun-cotton and nitro-glycerin will, however, withstand this
temperature for a long time without serious detriment, excepting that
nitro-glycerin is slightly volatilized. When incorporated in cordite,
however, the nitro-glycerin appears to be much less volatile than when
free at this temperature. Under reduced pressure (3 or 4 in. only of
mercury instead of 30) it is possible to distil away a considerable
amount of nitro-glycerin from cordite at 100 deg. C. It is very doubtful
whether at ordinary temperatures and pressures any nitro-glycerin
whatever evaporates.

Cordite may be kept in contact with clean, dry metals, wood, paper, and
a number of ordinary substances without deterioration. In contact with
damp and easily oxidizable metals all the substances of the gun-cotton
class are liable to a slight local action, but the colloid nature, and
probably also the contained mineral jelly, protect cordite considerably
in these circumstances. Ammonia has a deleterious action, but even this
proceeds but slowly. Cordite does not appear to change when kept under
water.

The manufacturing processes comprise: drying the gun-cotton and
nitro-glycerin; melting and filtering the mineral jelly; weighing and
mixing the nitro-glycerin with the gun-cotton; moistening this mixture
with acetone until it becomes a jelly; and then incorporating in a
special mixing mill for about three hours, after which the weighed
amount of mineral jelly is added and the incorporation continued for
about one hour or until judged complete. The incorporating or mixing
machine is covered as closely as possible to prevent too great
evaporation of the very volatile acetone. Before complete incorporation
the mixture is termed, in the works, "paste," and, when finally mixed,
"dough."

The right consistency having been produced, the material is placed in a
steel cylinder provided with an arrangement of dies or holes of
regulated size at one end, and a piston or plunger at the other. The
plunger is worked either by hydraulic power or by a screw (driven from
ordinary shaf