THE ROYAL ARTILLERY INSTITUTION. 
73 
If the use of the full blasting power has to be made subordinate to other 
considerations the equivalent proportion is somewhat reduced. 
Under water its powers are developed to their full extent, and promise to 
make it a tremendous agent for the destruction of ships, or for the operations 
by which harbour entrances and important channels may be defended and 
attacked. The examples cited on this point are, first, that two tiers of piles 
10 in. thick, with stones between them, were swept away by the explosion of 
a barrel with 100 lbs. of gun-cotton. The water was 13 ft. deep ; the barrel 
was 8 ft. below the surface, and 3 ft. from the face of the piles. The 
discharge made a clean sweep through a radius of 15 ft., and raised the 
water 200 ft. Secondly, a barrel containing 400 lbs. was exploded in 10 ft. 
of water, at 18 ft. distance from a sloop. The sloop was shattered to 
pieces, and its fragments were thrown to a height of 400 ft. 
As an instance of the comparative effect against woodwork, such as would 
be constructed by military engineers, it is stated that a box containing 
25 lbs. of gun-cotton cut a clean opening, 9 ft. wide, through a double row 
of strong palisades. The palisades in the front row were 12 inches in 
diameter, 8 ft. high, and driven 3 ft. into the ground; the back row were 
8 inches in diameter. Three times the same quantity of gunpowder had 
no effect whatever except that the piles were blackened by the explosion. 
A similar box, laid on the centre of a strong oak bridge, 24 ft. span, and 
made of 12 in. scantling, shattered the timber to atoms. 
Keeping qualities of Gun-cotton. 
Supposing, however, that all difficulties in controlling the rate of explo¬ 
sion and ensuring uniformity of strength were overcome, that the results 
were equal to the best anticipations, and that gun-cotton was admitted to be 
an improvement on gunpowder as a means of throwing projectiles or creating 
explosions, it would be necessary to become assured that these qualities were 
permanent under proper care; and it would have to be shown that neither 
heat nor damp induced any great loss of strength or any dangerous 
tendencies. This inquiry is especially necessary and important because the 
gun-cotton made at the time of its first invention was undoubtedly subject 
to such chemical changes as tended to produce entire decomposition and 
threatened to cause spontaneous explosion. It is manifest that any danger 
of this kind, if not entirely removed, would be fatal to the introduction of 
the material into the service. 
With regard to spontaneous ignition the supporters of gun-cotton 
maintain that no chance of such a catastrophe exists now that the present 
mode of manufacture is adopted. They attribute the dangerous properties 
of the early gun-cotton to its not being washed enough to purify it 
thoroughly from all superfluous or free ” acid; and they cite the opinion 
given, after careful investigation, by a Committee of Chemical Professors in 
Austria, that “ experimental proofs demonstrate that Lenk’s gun-cotton 
is not spontaneously combustible/'’ On the other hand indications have 
been noticed, both abroad and in this country, that some acid re-action or 
some chemical change does take place, especially when the gun-cotton is 
exposed to sunlight, and these indications cause some suspicion that the 
[yol. iy.] 10 
