140 
CAPTAIN NOBLE AND ME. F. A. ABEL ON FIEED GUNPOWDER. 
Experiment 8, June 29, 1871. — Fired 1586 grs. (102-77 grms.) pebble powder in 
cylinder No. 6. There was a slight escape of gas at first, but the plug soon tightened. 
Gas collected and sealed immediately. 
On opening the cylinder the deposit was found principally at the bottom. It 
adhered very firmly, and was removed with great difficulty. 
The colour of the smooth surface was light grey and green, buff in one or two places. 
Fracture yellowish green. 
The portions of the residue that could not be removed with a chisel were dissolved 
out. 
The firing copper wires -07 in diameter were melted and had formed a button, having, 
however, rather long stumps. 
c. A. a. Crush, tin. Pressure in tons. 
•1064 -1667 -0833 -033 1-28 
Experiment 9, June 29, 1871. — Fired 4725 grs. (306-18 grms.) pebble in cylinder 
No. 4. 
On firing there was a slight escape of gas past the crusher-gauge. 
The gases were collected within five minutes of the explosion ; and after the tubes 
were sealed a rough measurement was made of the remaining quantity of gas, which 
amounted to 59,000 cub. centims. 
The residue was very easily detached from the cylinder. It was darker grey on the 
surface than in the last experiment. The fracture 
was a deep olive-green with a stratum of light 
grey in the middle, thus (see figure). 
The deposit was all on the bottom, excepting a 
very thin coating on the sides. Firing-wires fused 
level with the plug. 
g a Crush, copper Pressure 
cylinder. in tons. 
•3171 -1667 -0833 -018 4-90 
Experiment 10, July 5, 1871. — Fired 6344 grs. (411-09 grms.) P. powder in cylinder 
No. 6. Most of the gas escaped before enough could be collected. 
Residue was found, when the cylinder was opened, at the bottom, not in the usual 
hard compact mass, but much looser in texture. 
On the surface there were three large spongy 
projections, presenting an appearance as if the 
surface had been broken by the escape of oc. 
eluded gas, thus (see figure). 
Colour of surface grey in parts, also light 
