British Association. 293 
weight of powder, and occupying a space of one and one-tenth of the 
length of the powder cartridge. In regard to safety, it was a fact that 
during the ten years of the manufacture of General Leuk’s gun-cotton at 
the imperial factory at Kirtenberg, and during ten years’ storage of that 
material in the imperial magazines at Steinfeldt, in which thousands of 
ewts. were deposited, not one single accident occurred. The best tem- 
perature for gun-cotton was 136 centigrade, or between 277 and 338 
Fahrenheit—a temperature sufficiently high to ensure safety for all prac- 
tical purposes. The cost of production was considerably less than that 
of gunpowder, the price and quantities being compared which will pro- 
duce equal effects. As to the mechanical purposes of the cotton, it is 
used for artillery in the form of gun-cotton thread or spun-yarn. In this 
simple form, it would conduct combustion slowly in the open air at the 
rate of not more than one second. This thread was woven into a texture 
or circular web. ‘These webs were made of various diameters, and out of 
them cotton rifle cartridges were made by cutting them into the proper 
length. ‘The cotton web was generally enclosed in India-rubber tubes, 
in which form it is most convenient. For the explosion of mines it is 
used in the form of ropes. Conveyance and Storage of Gun-Cotton.—One 
pound of gun-cotton produces effects somewhat exceeding 3 lbs. of gun- 
powder in artillery.. This is a material advantage, whether it be carried 
by men, by horses, or in waggons. It may be placed in a store and 
preserved with great safety. The danger from explosion does not arise 
until it is confined. It may become damp, and even perfectly wet, and, 
without injury, may be dried by mere exposure to the air. Practical 
Use in Artillery —The gun keeps clean, and requires less windage, and 
therefore performs much better in continuous firing. In gunpowder there 
is 68 per cent. of refuse, or the matter of fouling. In gun-cotton there 
is no residuum, and therefore no fouling. Experiments made by the 
Austrian committee proved that 100 lbs. could be fired with gun-cotton 
against 30 lbs. of gun-powder. From the low temperature produced by 
gun-cotton, the gun does not heat. Experiments showed that 100 lbs. 
were fired with a 6-pounder in thirty-four minutes, and the heat was 
raised by gun-cotton to only 122 degrees of Fahrenheit; whilst 100 lbs. 
of gunpowder took 100 minutes, and raised the temperature to such a 
degree that water was instantly evaporated. The firing with the gun- 
powder was therefore discontinued, but the rapid firing with the gun- 
cotton was continued up to 180 lbs. without any inconvenience. The 
absence of fouling allows the mechanism of a gun to have more exactness 
than where allowance is made for fouling. The absence of smoke 
permits rapid firing and exact time. ‘The fact of smaller recoil from a 
gun-charged with gun-cotton is established by direct experiments. Its 
value is two-thirds of the recoil from gun-powder, the projectile being 
equal. Practical Application to Destructive Explosion.—lt is ascer- 
tained that the same shell is exploded by the same volume of gas gene- 
rated from gun cotton and gun-powder into more than double the num- 
ber of pieces ; and it is a startling fact, that the stronger and thicker the 
shell the smaller and more numerous are the fragments, Mining Uses.— 
The fact that the action of the gun-cotton is violent and rapid in exact 
proportion to the resistance it encounters, tells us the secret of the far 
higher efficacy of gun-cotton in mining than gun-powder. The stronger 
the rock, the less gun-cotton comparatively with gun-powder is found 
necessary for the effect—so much so that while gun-cotton is stronger than 
gun-powder, weight for weight, as three to one in artillery, it is stronger in 
the proportion 6:27 to that of strong solid rock, weight for weight. It is 
NEW SERIES—VOL. XVIII. NO, II1.—OCTOBER 1868. 2p 
