SHORT NOTES ON PROFESSIONAL SUBJECTS. 
US 
90. Report of Progress, Committee on Explosive Substances, 
Jan. 1, 1871.—The proceedings of the Committee on Explosive Substances, in 
continuation of those noticed in the Memorandum of Progress dated 7th July, 
1870,* have embraced the following experiments with gunpowder:— 
(A.) Conclusion of experiments with the 10-inch gun, fitted with plugs for 
crusher gauges and the chronoscope apparatus, in its smooth-bored state. 
( B .) Commencement of experiments with the same gun in a rifled state. 
(C.) Various experiments with the 8-inch gun, similarly fitted. 
(D.) Practice from a 12-inch 25-ton rifled gun, fitted with two plugs for crusher 
gauges. 
(E.) Practice from rifled service guns of 7 in. calibre and upwards, for the 
observation of velocities and determination of the range tables applicable to pebble 
powder. 
(-F.) The use of projectiles, fitted with plugs in their bases, to contain crusher 
apparatus similar in action to those used in the experimental guns. 
( G -.) The Committee have also made some preliminary trials with a new mate¬ 
rial, called picric powder, proposed as a bursting charge for shells, by Mr. Abel* 
Chemist to the War Department. They have tested, by firing for range and 
accuracy, some gun-cotton cartridges for small-arms, prepared by Mr. Punshon; 
and they have likewise tried a description of powder, submitted by Mr. Hahn, as 
a substitute for gunpowder in all its applications. 
(A.) 10-inch Experimental Gun, No . 375 , Smooth-bore. 
117 experimental rounds were fired from this gun before rifling the bore; 97 of 
these were noticed in the Memorandum of 7th July, 1870, the remaining 20 con¬ 
sisted of L.G., pebble, and pellet powders; viz.:— 
6 rounds of L.G. charge 60 lbs. 
6 /, Pebble. n 70 lbs. 
6 „ Pellet .. // 64 lbs. 
2 // Spherical pellet. » 64 lbs. and 70 lbs. 
The L.G. powder was fired with the view of comparing its effects with those of 
R.L.G. Similar trials were made with the 8-inch experimental gun, and the 
detailed results are given at p. 146. In the 10-inch gun the mean velocities with 
L.G. were about 50 ft. lower than with R.L.G.; the mean maximum pressures 
were also lower; but the pressures on individual crusher plugs were occasionally 
as high as would be given by R.L.G.; the pressure on A crusher varying from 
46 tons to 54 J tons on the square inch. 
The pellet powders proved inferior to the pebble; the pressures being fully as 
high, whilst the velocities were about 50 ft. per second less. 
The mean results of the above 20 rounds were as follow:— 
* Vide “ Short Notes on Professional Subjects,” p. 128. 
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