very satisfactory when it happens to an enemy, but not when it happens to one’s-self, therefore when we have to enter an enemy’s harbour we countermine. This operation is now about to be illustrated. The last experiments exhibited the power of offensive torpedoes. There are several different kinds, such as Mr Whitehead’s fish-torpedo, the Harvey torpedo, and others.”

“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 

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