“Behind the vessel was a place, above the rudder, for carrying a large powder magazine. This was made of two pieces of oak timber, large enough, when hollowed out, to contain an hundred and fifty pounds of powder, with the apparatus used in firing it. A rope extended from the magazine to the wood-screw above mentioned; when the wood-screw was fixed, and to be cast off from its tube, the magazine was to be cast off likewise, leaving it hanging to the wood-screw. It was lighter than water, that it might rise up against the object to which the screw and itself were fastened. “Within the magazine was a clock, constructed to run any proposed length of time under twelve hours; when it had run out its time, it unpinioned a strong lock, resembling a gun-lock, which gave fire to the powder. This apparatus was so pinioned that it could not possibly move till, by casting off the magazine from the vessel, it was set in motion. “The skilful operator could swim so low on the surface as to approach very near a ship in the night without fear of being discovered, and might, if he chose, approach the stem or stern with very little danger. He could sink very quickly, keep at any necessary depth, and row a great distance in any direction he desired without coming to the surface. When he rose to the surface he could soon obtain a fresh supply of air, and, if necessary, he might then descend again and pursue his course. “EXPERIMENTS MADE TO PROVE THE NATURE AND USE OF A SUBMARINE VESSEL. “The first experiment I made was with about two ounces of powder, which I exploded four feet under water, to prove to some of the first personages in Connecticut that powder would take fire under water. “The second experiment was made with two pounds of powder, enclosed in a wooden bottle, and fired under a hogshead, with a two-inch oak plank between the hogshead and the powder; the hogshead was loaded with stones, as deep as it could swim. A wooden pipe, descending through the lower head of the hogshead and through the plank into the powder contained in the bottle, was primed with powder. A match put to the priming exploded the powder with a great effect, rending the plank into pieces, demolishing the hogshead, and casting the stones and ruins of the hogshead, with a body of water, many feet into the air, to the astonishment of the spectators. This experiment was likewise made for the satisfaction of the gentlemen above mentioned. “I afterwards made many experiments of a similar nature, some with large quantities of powder.