270 
IMPROVEMENTS IN GUN-COTTON. 
lb. have to be projected in addition to the shot, and at a much higher speed. The re¬ 
mainder, General von Lenk attributes to the different law of combustion. But the fact 
is established. The comparative advantages of gun-cotton and gunpowder for producing 
high velocities, are shown in the following experiment with a Krupp’s cast-steel gun, 6- 
pounder. With ordinary charge 30 oz. of powder produced 1338 ft. per second. 
With charge of 13-| oz., gun-cotton produced 1563 ft. The comparative advantages in 
shortness of gun are shown in the following experiments, 12-pounder:—- 
Velocity: 
Calibres. Charge. feet per second. 
Cotton, length 10 . 15-9 oz.. 1426 
Powder, ,, 13£ . 49 (normal powder charge)... 1400 
Cotton, „ 9 . 17 . 1402 
As to advantage in weight of gun, the fact of the recoil being less in the ratio of 2:3 
enables a less weight of gun to be employed, as well as a shorter gun, without the disad¬ 
vantage to practice arising from lightness of gun. As regards durance of gun, bronze 
and cast-iron guns have been fired 1000 rounds without in the least affecting the endu¬ 
rance of the gun. As regards its practical application to destructive explosions of shells, 
it appears that from a difference in the law of expansion, arising probably from the pres¬ 
sure of water in intensely-heated steam, there is an extraordinary difference of result, 
namely, that the same shell is exploded by the same volume of gas into more than double 
the number of pieces. This is to be accounted for by the greater velocity of 
explosion when the gun-cotton is confined very closely in very small spaces. It 
is also a peculiarity that the stronger the shell, the smaller the fragments into 
which it is broken. As regards mining uses, the fact that the action of gun-cotton 
is violent and rapid in exact proportion to the resistance it encounters, tells us the 
secret of its far higher efficacy in mining than gunpowder. The stronger the rock, the 
less gun-cotton, comparatively with gunpowder, is necessary for the effect; so much so 
that while gun-cotton is stronger than powder as 3 to 1 in artillery, it is stronger in the 
proportion of 6*274 to 1 in a strong and solid rock, weight for weight. It is the hollow- 
rope form which is used for blasting. Its power of splitting up the material is regulated 
exactly as wished. As regards military and submarine explosion, it is a well-known fact, 
that a bag of gunpowder nailed on the gates of a city will blow them open. In this 
case gun-cotton would fail. A bag of gun-cotton exploded in the same way is power¬ 
less. If one ounce of gunpowder is exploded in scales, the balance is thrown down; 
with an equal force of gun-cotton nothing happens. To blow up the gates of a city a 
very few pounds of gun-cotton, carried in the hand of a single man, will be sufficient,— 
only he must know its nature. In a bag it is harmless ; exploded in a box it will shatter 
the gates to atoms. Against the palisades of a fortification : a small square box con¬ 
taining 25 lb., merely flung down close to it, will open a passage for troops; in actual 
experience on palisades a foot diameter and 8 feet high, piled in the ground, backed by 
a second row of 8 inches diameter, a box of 25 lb. cut a clean opening 9 feet wide. To 
this three times the weight of gunpowder produced no effect whatever, except to blacken 
the piles. Against bridges : a strong bridge of oak, 24 feet span, w r as shattered to atoms 
by a small box of 25 lb. laid on its centre; the bridge was not broken, it was shivered. 
As to its effects underwater: in the case of two tiers of piles, in water 13 feet deep, 10 
inches apart, with stones between them, a barrel of 100 lb. gun-cotton, placed 3 feet 
from the face and 8 feet under water, made a clean sweep through a radius of 15 feet, 
and raised the water 200 feet. In Venice, a barrel of 400 lb. placed near a sloop in 10 
feet water, at 18 feet distance, threw it in atoms to a height of 400 feet. All experiments 
made by the Austrian Artillery Committee were conducted on a grand scale,—36 bat¬ 
teries, six and twelve pounders (gun-cotton) having been constructed, and practised with 
that material. The reports of the Austrian Commissioners are all based on trials with 
ordnance, from six pounders to forty-eight pounders, smooth bore and rifled cannon. The 
trials with small fire-arms have been comparatively few, and are not reported on. The 
trials for blasting and mining purposes were also made on a large scale by the Imperial 
Engineers' Committee, and several reports have been printed on the subject. 
