the
following results:--The charge used was 5 lbs. 8 oz., the size of the
cubes being 0.2 inch. The mean crusher-gauge pressure was 14.3 tons per
square inch (maximum, 2,210; minimum, 2,142), and average pressure 2,180
atmospheres. The muzzle velocity was 2,140 foot seconds, and the muzzle
energy 1,429 foot tons. A gramme of ballistite generates 615 c.c. of
permanent gases, and gives rise to 1,365 grm. units of heat. Ballistite is
manufactured at Ardeer in Scotland, at Chilworth in Surrey, and also in
Italy, under the name of Filite, which is in the form of cords instead of
cubes. The ballistite made in Germany contained more nitro-cellulose, and
the finished powder was coated with graphite. Its use has been
discontinued as the Service powder in Germany, but it is still the Service
powder in Italy.

[Footnote A: _Proc. Roy. Soc._, vol. lii., p. 315.]

~U.S. Naval Smokeless Powder.~--This powder is manufactured at the U.S.
Naval Torpedo Station for use in guns of all calibres in the U.S. Navy. It
is a nitro-cellulose powder, a mixture of insoluble and soluble nitro-
cellulose together with the nitrates of barium and potassium, and a small
percentage of calcium carbonate. The proportions in the case of the powder
for the 6-inch rapid-fire gun are as follows:--Mixed nitro-cellulose
(soluble and insoluble) 80 parts, barium nitrate 15 parts, potassium
nitrate 4 parts, and calcium carbonate 1 part. The percentage of nitrogen
contained in the insoluble nitro-cellulose must be 13.30+-0.15, and in the
soluble 11.60+-0.15, and the mean nitration strength of the mixture must be
12.75 per cent. of nitrogen. The solvent used in making the powder is a
mixture of ether (sp. gr. 0.720) 2 parts, and alcohol (95 per cent. by
volume) 1 part. The process of manufacture is briefly as follows:[A]--The
soluble and insoluble nitro-cellulose are dried separately at a
temperature from 38 deg. to 41 deg. C., until they do not contain more than 0.1
per cent. of moisture. The calcium carbonate is also finely pulverised and
dried, and is added to the mixed nitro-celluloses after they have been
sifted through a 16-mesh sieve. The nitrates are next weighed out and
dissolved in hot water, and to this solution is added the mixture of
nitro-celluloses and calcium carbonate with constant stirring until the
entire mass becomes a homogeneous paste. This pasty mass is next spread
upon trays and re-dried at a temperature between 38 deg. and 48 deg. C., and w