Hollow Dynamite Cartridge.
View from below.
In fact, the amount of explosives consumed in the industries is so great that the quantity employed for military purposes sinks into insignificance. Yet we have failed to refer to those industries—quarrying and mining, and the engineering operations—in which they are most extensively and commonly used, being employed so largely in mining alone that it is an almost daily occurrence for blasts containing twenty, thirty, and even fifty thousand pounds of explosives to be used in a single charge; and the system of large blasts has even become common in hard-rock excavations, such as quarries and railroad cuttings, while in the blast at the blowing up of Flood Rock, in New York Harbor, October 10, 1885, over one hundred and forty-one tons of rack-a-rock, dynamite, and mercury fulminate were used in a single shot.
Nor have I alluded to the use of explosives by the anarchists in their dastardly outrages, through which the safety of the old and young, feeble and strong, the innocent and the offending, are alike endangered; but I will touch briefly upon the applications of these powerful agents in the too-much cultivated industry of safe-robbing, since I was called upon some years ago to demonstrate, before a Government commission, how safes might be successfully attacked either in a burglarious way or by a mob with explosives, meaning by the burglarious operation that the safe should be made accessible within twenty-four hours with means such as a party of men could smuggle into a bank and which might be used without attracting attention or doing material damage to the building, and by “mob violence,” meaning that the vaults are supposed to be in the hands of a mob which has ample time and quantities of explosives at command, and does not care how much noise is made or destruction is wrought, provided the treasure is secured.
Firing on Iron Disk, resting on Lead Disk, in testing the Efficiency of Gun Cotton.
Gun Cotton Disk. With indented inscription, and iron plate upon which the indented inscription has been reproduced.
In the experiments made in a burglarious way, among others, a three-thousand-dollar square safe of the most approved construction was attacked by inserting in the crevice about the locked door four and eight tenths ounces of nitroglycerin, and in eight minutes after the operation of loading was begun the charge was fired, with the result that the whole of the jamb below the door was blown out and a hole made in the door of sufficient size to admit the hand and arm, while the doors and divisions of the interior compartments were completely shattered. On repeating the operation with four ounces and a quarter of forcite dynamite the door was completely torn off.
Among experiments made to demonstrate the resistance of structures to attack by a mob was one upon a safe twenty-nine inches cube, with walls four inches and three quarters thick, made up of plates of iron and steel, which were re-enforced on each edge so as to make it highly resisting, yet when a hollow charge of dynamite nine pounds and a half in weight and untamped was detonated on it a hole three inches in diameter was blown clear through the wall, though a solid cartridge of the same weight and of the same material produced no material effect. The hollow cartridge was made by tying the sticks of dynamite around a tin can, the open mouth of the latter being placed downward, and I was led to construct such hollow cartridge for use where a penetrating effect is desired by the following observations:
