tide the strain would be sufficient to set off the trigger. The torpedoes were launched at three fine frigates, the 'Minnesota' the 'Roanoke' and the 'Cumberland' (the blockading fleet off the mouth of the James River).
"Finding that they all missed, I attributed it to the fact that such a fuse could not burn under a pressure of 20 feet of water. The conjecture was confirmed by experiment. The fuse could burn very surely at the depth of 15 feet—never at 20 feet.
"Some time afterwards those torpedoes were discovered by the enemy. Spans, barrels, and barregas were soon got up, and carried off as relics.
"The enemy prevented any further attack in this way by dropping the end of his lower studding-sail boom in the water every night, anchoring boats or beams ahead, &c. The first vessel destroyed by a torpedo was the 'Quaker City'—I think that was the name—in the Yazoo River. This torpedo was an old demi-john filled with powder, planted in the channel-way, and having a string attached to a friction-tube leading to the shore; the observer, with it in his hand, being concealed on the bank. She came; he pulled, and down she went.
"After this hasty sketch, I come to electrical torpedoes for guarding mountain-passes and roadways, &c., for the protection of strongholds, and the defence of fortified positions. Shells cast for the purpose should be used, but in an emergency tin canisters, or any other prefectly water-tight cases, will answer. I am not aware that electricity was used by either of the belligerents in the late American war for springing mines on land.
"The cases for land-torpedoes should be shells cast expressly for the purpose. The thickness of the shell being from one-fourth to an inch, and even more, or less, according to the size and the probable handling in transportation.
