|
| ENERGIES REPRESENTED BY ABOVE VELOCITIES. |
|________________________________________________________________________|
| | | | | |
| |Foot Tons.|Foot Tons.|Foot Tons.|Foot Tons.|
| | | | | |
| Cordite 0.4 inch | 5,413 | 5,994 | 6,950 | 7,478 |
| Ballistite 0.3 inch cubes | 4,227 | 4,754 | 5,479 | 5,852 |
| French B.N. | 4,047 | 4,463 | 5,104 | 5,460 |
| Prismatic amide | 3,507 | 3,862 | 4.460 | 4,745 |
|____________________________|__________|__________|__________|__________|

And again, in speaking of his own experiments, he says: "One 4.7-inch gun
has fired 1,219 rounds, and another 953, all with full charges of cordite,
while a 6-inch gun has fired 588 rounds with full charges, of which 355
were cordite. In the whole of these guns, so far as I can judge, the
erosion is certainly not greater than with ordinary powder, and differs
from it remarkably in appearance. With ordinary powder a gun, when much
eroded, is deeply furrowed (these furrows having a great tendency to
develop into cracks), and presents much the appearance in miniature of a
very roughly ploughed field. With cordite, on the contrary, the surface
appears to be pretty smoothly swept away, while the length of the surface
eroded is considerably less."

[Illustration: FIG. 39.--COMPARATIVE PRESSURE CURVES OF CORDITE AND BLACK
POWDER. _a_, Charge, 48 lbs. powder; _b_, charge, 13 lbs. 4 oz. cordite;
_c_, charge, 13 lbs. 4 oz. powder. Weight of projectile, 100 lbs. in
6-inch gun. M.V. Cordite = 1960 feet seconds.]

The pressures given by cordite compared with those given by black powder
in the 6-inch gun will be seen upon reference to Fig. 39, which is taken
from Professor V.B. Lewes's paper, read before the Society of Arts; and
due to Dr W. Anderson, F.R.S., the Director-General of Ordnance Factories.

It has been found that the erosive effect is in direct proportion to the
nitro-glycerine present. The cordite M.D., which contains only 30 per
cent. nitro-glycerine, gives only about half the erosive effect of the old
service cordite. With regard to the heating effect of cordite and cordite
M.D. on a rifle, Mr T.W. Jones made some experiments. He fired fifty
rounds of .303 cartridge