The second experiment was made with 2 lbs. of powder enclosed in a wooden bottle and fixed under a hogshead, with a 2–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, which produced a very great effect, rending the plank into pieces, demolishing the hogshead, and casting the stones and the 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 of them with large quantities of powder; they produced very violent explosions, much more than sufficient for any purpose I had in view. In the first essays with the submarine vessel I took care to prove its strength to sustain the great pressure of the incumbent water when sunk deep before I trusted any person to descend much below the surface, and I never suffered any person to go under water without having a strong piece of rigging made fast to it, until I found him well acquainted with the operations necessary for his safety. After that I made him descend and continue at particular depths, without rising or sinking, row by the compass, approach a vessel, go under her, and fix the wood screw mentioned in No. 2, and marked A, into her bottom, &c., until I thought him sufficiently expert to put my design into execution. I found, agreeably to my expectations, that it required many trials to make a person of common ingenuity a skilful operator. The first I employed was very ingenious, and made himself master of the business, but was taken sick in the campaign of 1776 at New York before he had an opportunity to make use of his skill, and never recovered his health sufficiently afterwards.