ON THE APPLICATION OF GUN-COTTON TO WARLIKE PURPOSES. 7 
steel gun, 6-pounder. An ordinary charge, 30 ounces powder, produced 
1338 feet per second. A charge of 134 oz. gun-cotton produced 1563 feet. 
The comparative advantage in shortness of gun is shown in the following 
experiments with a 12-pounder :— 
Charge. Length of gun. _— Velocity. 
Gunpowder ........4..... 49-0 oz.* 134 calibres. 1400 
PPAMMCOMOD 6. 6 co 6 os a's 159) og 10 . 1426 
ES ae ea ee Bly ia | A 9 9 1402 
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 disadvantage to practice arising from lightness of gun. (L. 5.) 
Endurance of gun.—Bronze and cast iron guns have been fired 1000 rounds 
without in the least affecting the endurance of the gun. 
Application to destructive explosions. Explosion of Shells——From some 
unexplained difference in the action of gun-cotton, there is an extraordinary 
difference of result as compared with gunpowder ; namely, the same shell is 
exploded by the same quantity of gas into more than double the number of 
pieces. This is partly 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. (L. 17.) 
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 artil- 
lery, it is stronger in the proportion of 6:274:1 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 can be regulated at will. 
Against the gates of a city—It is a well-known fact that a bag of gun- 
powder 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 
powerless. If 1 ounce of gunpowder is exploded in scales the balance is 
thrown down ; with an equal force of gun-cotton the scale-pan is not de- 
pressed. To blowup 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 containing 
25 Ibs. merely flung down close to them, will open a passage for troops. In 
an actual experiment on palisades a foot diameter and 8 feet high, driven 3 
feet into the ground, backed by a second row of 8 inches diameter, a box of 
25 Ibs. cut a clean opening 9 feet wide. On this three times the weight of 
gunpowder produced no effect whatever, except to blacken the piles. 
Against bridges.—A strong bridge of oak, 12 inches scantling, 24 feet span, 
was shattered to atoms by a small box of 25 lbs. laid on its centre: the bridge 
was not broken, it was shivered. 
Under water.—Two tiers of piles 10 inches thick, in water 13 feet deep, 
With stones between them, were blown up by a barrel of 100 Ibs. gun-cotton 
placed 3 feet from the face, and 8 feet under water. It made a clean sweep 
through a radius of 15 feet, and raised the water 200 feet. In Venice, a 
* Ordinary charge of powder. 
