“Ha, that is one of the strange peculiarities of gun-cotton,” replied Firebrand, with an amused look; “you don’t require to keep it dry like powder. It is only necessary that there should be one small lump of dry gun-cotton inside the wet stuff, with a detonator in its heart. A detonator, you must know—”
“Oh, I know what a detonator is,” said my mother, quickly.
“Well then,” continued Firebrand, “the exploding of the detonator and the dry disc causes the wet gun-cotton also to go off, as you have seen. Now they are going to exhibit one of the modes of defending harbours. They have sunk four mines, of 300 pounds of gunpowder each, not far from where you see yon black specks floating on the water. The black specks are buoys, called circuit-closers, because they contain a delicate contrivance—a compound of mechanism and galvanism—which, when the buoys are bumped, close the electric circuit and cause the mine to explode. Thus when a ship-of-war sails against one of these circuit-closers, she is immediately blown up.”
“Is not that rather a sneaking way of killing one’s enemies?” asked my mother.
Young Firebrand laughed, and admitted that it was, but pleaded that everything was fair in love and war.
In actual warfare the circuit-closers are placed just over the mines which they are designed to explode, but for safety on this occasion they were placed at a safe distance from their respective mines. A steam-launch was used to bump them, and a prodigious upheaval of water on each explosion showed clearly enough what would have been the fate of an iron-clad if she had been over the mine.
“Oh, shade of Nelson!” I could not help exclaiming, “how shocked you must be if you are permitted to witness such methods of conducting war.”
“Ah, yes!” sighed Firebrand; “the bubble reputation, you see, is being transferred from the cannon’s mouth to the torpedo.”
I made no reply, for my mind reverted to my laboratory in Devonshire, where lay the working-model of the terrible weapon I had spent so much time in perfecting. It seemed strange to me now, that, in the eager pursuit of a scientific object, I had scarcely ever, if at all, reflected on the dire results that the use of my torpedo involved, and I felt as if I were really guilty of the intent to murder. Just before leaving home I had charged my model, which was quite a large one, capable of holding about 50 pounds of dynamite, in the hope that I might prevail on the First Lord of the Admiralty and some of his colleagues to come down and see it actually fired. I now resolved to throw the dynamite into the sea, break up my model, and have done with explosives for ever.
While my mind was running on this, I was startled by an explosion close alongside. On turning towards the side of the ship, I found that it was caused by the rending of a huge iron chain, the links of which were more than one and a quarter inch in thickness. This powerful cable, which could have held an iron-clad, was snapped in twain like a piece of thread by the explosion against it of only two and a half pounds of gun-cotton.