40 rounds of black powder, and 249 rounds of cordite (58
per cent. nitro-glycerine) and was still in excellent condition, and
showed very little sign of action, and also a 12-lb. B.L. gun that had
been much used and was in no wise injured.

[Footnote A: The gun-cotton used contains 12 per cent. of soluble
gun-cotton, and a nitrogen content of not less than 12.8 to 13.1 per cent.]

[Illustration: Fig. 37 Scale, 1 inch = 1 foot. Single Strand Reel.]

[Illustration: FIG. 38.--"TEN-STRANDING."]

In some experiments made by Captain Sir A. Noble,[A] with the old cordite
containing 58 per cent. nitro-glycerine, a charge of 5 lbs. 10 oz. of
cordite of 0.2 inch diameter was fired. The mean chamber crusher gauge
pressure was 13.3 tons per square inch (maximum 13.6, minimum 12.9), or a
mean of 2,027 atmospheres (max. 2,070, min. 1,970). The muzzle velocity
was 2,146 foot seconds, and the muzzle energy 1,437 foot tons. A gramme of
cordite generated 700 c.c. of permanent gases at 0 deg. C. and 760 mm.
pressure. The quantity of heat developed was 1,260 gramme units. In the
case of cordite, as also with ballistite, a considerable quantity of
aqueous vapour has to be added to the permanent gases formed. A similar
trial, in which 12 lbs. of ordinary pebble powder was used, gave a
pressure of 15.9 tons per square inch, or a mean of 2,424 atmospheres. It
gave a 45-lb. projectile a mean muzzle velocity of 1,839 foot seconds,
thus developing a muzzle energy of 1,055 foot tons. A gramme of this
powder at 0 deg. C. and 760 mm. generates 280 c.c. of permanent gases, and
develops 720 grm. units of heat.

[Footnote A: _Proc. Roy. Soc._, vol. lii., No. 315.]

In a series of experiments conducted by the War Office Chemical Committee
on Explosives in 1891, it was conclusively shown that considerable
quantities of cordite may be burnt away without explosion. A number of
wooden cases, containing 500 to 600 lbs. each of cordite, were placed upon
a large bonfire of wood, and burned for over a quarter of an hour without
explosion. At Woolwich in 1892 a brown paper packet containing ten cordite
cartridges was fired into with a rifle (.303) loaded with cordite, without
the explosion of a single one of them, which shows its insensibility to
shock.

With respect to the action of cordite upon guns, Sir A. Noble points out
that the erosion caused is of a totally different kind to that of black
powder. The surface of the barrel in the case of cordite ap