IMPROVEMENTS IN GUN-COTTON. 
275 
be distributed and opened out mechanically, so as to occupy a larger space, and 
in this state it can be made to act even more slowly than gunpowder; and the 
exact limit for purposes of artillery General von Lenk has found by critical experiments. 
In general, it is found that the proportion of 11 lb. of gun-cotton, occupying 1 cubic 
foot of space, produces a greater force than gunpowder, of which from 50 to 60 lb. 
occupies the same space, and a force of the nature required for ordinary artillery. But 
each gun and each kind of projectile requires a certain density of cartridge. Practically, 
gun-cotton is most effective in guns when used as £ to £ weight of powder, and occu¬ 
pying a space of l^th of the length of the powder-cartridge. The mechanical struc¬ 
ture of the cartridge is of importance as affecting its ignition. The cartridge is formed 
of a mechanical arrangement of spun cords, and the distribution of these, the place and 
manner of ignition, the form and proportion of the cartridge, all affect the time of com¬ 
plete ignition. It is by the complete mastery he has gained over all these minute points 
that General von Lenk is enabled to give to the action of gun-cotton on the projectile 
any law of force he pleases. Its cost of production is considerably less than that of gun¬ 
powder, the price of quantities which will produce equal effects being compared. Gun¬ 
cotton is used for artillery in the form of a gun-cotton thread or spun yarn. In this 
simple form it will conduct combustion slowly in the open air, at a rate of not more than 
1 foot per second. This thread is w r oven into a texture or circular web. These webs are 
made of various diameters, and it is out of these webs that common rifle cartridges are 
made, merely by cutting them into the proper lengths, and enclosing them in stiff cylin¬ 
ders of pasteboard, which form the cartridges. (In this shape its combustion in the open 
air takes place at a speed of 10 feet per second.) In these cylindrical webs it is also used 
to fill explosive shells, as it can be conveniently employed in this shape to pass in through 
the neck of the shell. Gun-cotton thread is spun into ropes in the usual way, up to 2 
inches diameter, hollow in the centre. This is the form used for blasting and mining 
purposes; it combines great density with speedy explosion. The gun-cotton yarn is used 
directly to form cartridges for large guns by being wound round a bobbin so as to form 
a spindle like that used in spinning mills. The bobbin is a hollow tube of paper or 
wood ; the object of the wooden rod is to secure in all cases the necessary length of cham¬ 
ber in the gun required for the most effective explosion. The gun-cotton circular web 
is enclosed in close tubes of india-rubber cloth to form a match line, in which form it is 
most convenient, and travels with speed and certainty. In large quantities, for the explo¬ 
sion of mines, it is used in the form of rope, and in this form it is conveniently coiled in 
casks and stowed in boxes. As regards conveyance and storage of gun-cotton: it results 
from the foregoing facts, that 1 lb. of gun-cotton produces an effect exceeding 3 lb. of 
gunpowder in artillery. This is a material advantage, whether it be carried by men, by 
horses, or in waggons. It may be placed in 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 without injury, and may be dried by mere exposure to the air. This is of 
great value in ships of war, and in case of danger from fire, the magazine may be sub¬ 
merged without injury. As regards its practical use in artillery, it is easy to gather from 
the foregoing general facts how gun-cotton keeps the gun 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 there¬ 
fore no fouling. Experiments made by the Austrian Committee proved that 100 rounds 
could be fired with gun-cotton, against 30 rounds of gunpowder. From the low tempera¬ 
ture produced by gun-cotton the gun does not heat. Experiments showed that 100 
rounds were fired with a 6-pounder in 34 minutes, and the gun was raised by gun-cotton 
to only 122° Fahrenheit, whilst 100 rounds with gunpowder took 100 minutes, and raised 
the temperature to such a degree that water was instantly evaporated. The firing with 
the gunpowder was therefore discontinued; but the rapid firing w’ith the gun-cotton 
was continued up to 180 rounds without any inconvenience. The absence of fouling allows 
all the mechanism of a gun to have much more exactness than where allowance is made 
for fouling. The absence of smoke promotes rapid firing and exact aim. There are no 
poisonous gases, and the men suffer less inconvenience from firing in casemates, under 
hatches, or in closed chambers. The fact of smaller recoil from a gun charged with gun¬ 
cotton is established by direct experiment: its value is § of the recoil from gunpowder, 
projectile effect being equal. To understand this may not be easy. The waste of the 
solids of gunpowder accounts for one part of the saving, as in 100 lb. of gunpowder 68 
