152 CAPTAIN NOBLE AND MR. F. A. ABEL ON FIRED GUNPOWDER, 
with development of heat. It was got as rapidly as possible into the mill and was easily 
ground in dry nitrogen. This was sealed in bottle marked C, while some unground 
lumps were marked D. 
A mixture of the top and bottom was ground in nitrogen and was marked E. 
Transparent crystals (on firing-plug) also preserved in small tube. 
Crush, copper Pressure 
a " cylinder. in tons. 
•900 -0833 *0833 T18 27-2 
Experiment 70, October 20, 1873. — Fired 3800 grs. (246-286 grms.) E. L. G. by 
means of a detonator containing 2 grms. of fulminate of mercury. Cylinder perfectly 
tight. Eesidue full of lustrous scales, otherwise of usual appearance ; considerable 
lump of metal found in bottom (firing-wire and detonator-case). 
Crush, copper Pressure 
A - a ‘ cylinder. in tons. 
•500 -1667 *0833 -081 10-7 
Experiment 71, October 22, 1873. — Last experiment repeated with similar results. 
j. . Crush, copper Pressure 
a ' cylinder. in tons. 
•500 -1667 -0833 -086 11-10 
Experiment 72, October 24, 1873. — Fired, with a view to determine the amount of 
heat absorbed by a gun when fired, nine rounds of 1 lb. 12 oz. (793-788 grms.) E. L. G. 
in a 12-pr. B. L. gun; weight of shot 11 lbs. 12 oz. (5,329 - 72 grms.). Temperature of 
air 46°-2 F. 
Time of firing six minutes. After firing, the gun was at once placed in a vessel of 
water and the changes of temperature observed. The following are the data : — 
Weight of gun 387,141-6 grms. 
Weight of water . . . . . . 192,777-0 „ 
Temperature of gun and water before firing 47 o, 0 F. ; the heat communicated to 
the gun by nine rounds raised the common temperature of the gun and water to 
51°-15 F. 
Hence the heat raised the water and gun through 4°T5 F. = 2°-305 C. 
Experiment 73. — Fired five rounds 1-5 lb. (680-39 grms.) E. L. G. in a 12-pr. B. L. gun. 
Weight of shot . , 532 - 75 grms. 
Temperature of air 46°*5 F. 
Time of firing 2|- minutes. 
Weight of gun 387,141-6 grms. 
Weight of water 68,810-1 grms. 
Temperature of gun and water before firing . . . 45°-7 F. 
„ „ „ after „ ... 50 o, 55 F. 
