“Dear me,” said my mother, with a perplexed air, “I should have thought, Mr Firebrand, that all torpedoes were offensive.”
“By no means; those which are placed at the entrance of harbours and navigable rivers are defensive. To protect ourselves from the offensive weapon, we use crinolines.”
My mother looked quickly up at her polite young mentor. “You play with the ignorance of an old woman, sir,” she said, with a half-jocular air.
“Indeed I do not, madam, I assure you,” returned Firebrand, with much earnestness. “Every iron-clad is provided with a crinoline, which is a powerful iron network, hung all round the ship at some distance from her, like—pardon me—a lady’s crinoline, and is intended to intercept any torpedo that may be discharged against her.”
Attention was called, at this point, to the counter-mining experiments.
It may be said, in regard to these, that they can be conducted in various ways, but always with the same end in view, namely, to destroy an enemy’s mines by exploding others in their midst.
For the sake of illustration, it was supposed that the surrounding sea-bottom was studded with invisible torpedoes, and that the Nettle was a warship, determined to advance into the enemy’s harbour. To effect this with safety, and in order to clear away the supposed sunken torpedoes, a counter-torpedo was floated between two empty casks, and sent off floating in the desired direction by means of the tide. This countermine consisted of an iron cylinder, containing 300 pounds of powder, and was electrically connected with the Nettle. A small charge of gun-cotton was fixed to the suspender that held the torpedo to its casks. When at a safe distance from the ship, this charge was fired. It cut the suspender and let the torpedo sink to the bottom. There it was exploded with terrific violence, as was quickly shown by the mighty fountain of mud, water, and smoke that instantly shot up into the air. It has been proved by experiment that 500 pounds of gun-cotton exploded below water, will destroy all the torpedoes that lie within a radius of 120 yards. It is obvious, therefore, that a warship could advance into the space thus cleared and then send a second countermine ahead of her in the same way. If neither tide, current, nor wind will serve to drift the casks, the operation might be accomplished by a small boat, which could back out of danger after laying each torpedo, and thus, step by step, or shot by shot, the advance could be made in safety through the enemy’s defences.
After this, twelve small charges of gun-cotton were sunk in various directions, each representing a countermine of 500 pounds. These were discharged simultaneously, to demonstrate the possibility of extending the operations over a wide area. These miniature charges were sent down in small nets, and were quite unprotected from the water, so that the gun-cotton was wet when fired.
This fact caught the attention of my mother at once.
“How can it go off when wet?” she exclaimed, turning her bright little eyes in astonishment on her young companion.