4 REPORT—1863. 
General was indeed found to contain 2:33 per cent. of mineral matter, con- 
sisting chiefly of silica*, 
Much apprehension has been felt about the effect of the gases produced by 
the explosion of gun-cotton. It has been stated that both nitrous fumes and 
prussic acid are among these gases, and that the one would corrode the gun, 
and the other poison the artillerymen. Now, though it is true that from 
some kinds of gun-cotton, or by some methods of decomposition, one or both 
of these gases may be produced, the results of the explosion of the Austrian 
gun-cotton, without access of air, are found by Karolyi to contain neither of 
these, but to consist of nitrogen, carbonic acid, carbonic oxide, water, and a 
little hydrogen, and light carburetted hydrogen. (C. 7.) These are compara- 
tively innocuous; and it is distinctly in evidence that practically the gun is 
less injured by repeated charges of gun-cotton than of gunpowder, and that 
the men in casemates suffer less from its fumes. (L. 13.) The importance of 
this latter property in a fortress, or a ship, will be at once apparent. 
It seems a disadvantage of this material as compared with gunpowder that it 
explodes at a lower temperature, possibly at 136°C (277° F.); but against the 
greater liability to accident arising from this cause may be set the greatly 
diminished risk of explosion during the process of manufacture, since the gun- 
cotton is always immersed in liquid, except in the final drying; and that 
may be performed, if desirable, at the ordinary temperature of the air. Again, 
if it should be considered advisable at any time, it may be stored in water, 
and only dried in small quantities when required for use. 
The fact that gun-cotton is not injured by damp like gunpowder, is indeed 
one of its recommendations. It is not even so liable to absorb moisture from 
the atmosphere, 2 per cent. being the usual amount of hygroscopic moisture 
found in it; and should that quantity be increased through any extraordinary 
conditions of the air, the gun-cotton speedily parts with its excess of mois- 
ture when the air returns to its ordinary state of dryness, (A. 5 & 8.) 
But a still more important chemical advantage which gun-cotton possesses, 
arises from its being perfectly resolved into gases on explosion, so that there 
is no smoke to obscure the sight of the soldier who is firing, or to point out 
his position to the enemy; and no residue left in the gun to be got rid of 
before another charge can be introduced. 
2. Mechanical Considerations. 
At the outset of this inquiry the Mechanical Members of the Committee 
found it difficult to believe that greater effects are produced by a given volume 
of gases generated from gun-cotton than by an equal volume of gases 
generated from gunpowder; nevertheless, from the facts as brought before 
the Committee, such contradiction would at first sight appear to exist. 
The great waste of force in gunpowder constitutes an important difference 
between it and gun-cotton, in which there is no waste. According 
to the experiments of Bunsen and Schischkoff+, the waste in gunpowder 
is 68 per cent. of its own weight, and only 32 per cent. is useful. This 
68 per cent. is not only waste in itself, but it wastes the power of the 
remaining 32 per cent. It wastes it mechanically, by using up a large por- 
tion of the mechanical force of the useful gases. The waste of gunpowder 
issues from the gun with much higher velocity than the projectile; and if it 
* Two combustions of it, made by Dr. Gladstone, gave respectively 2°27 and 24 per 
cent. of ash. It was mainly insoluble silica in a state of very fine division, but acids 
dissolved out of it an appreciable amount of lime, 
t Pogg. Annal, 4th Series, vol. xii. p. 131, 
