“There was a piece of cork, with phosphorus on it, put into the water-gauge, condensing the air within, and bearing the cork on its surface. By the light of the phosphorus, the ascent of the water in the gauge was rendered visible, and the depth of the vessel ascertained by a graduated scale.
“An oar formed on the principle of the screw was fixed in the fore part of the vessel; its axis entered the vessel, and, being turned in one direction, rowed the vessel forward; but being turned in the other, rowed backward. It was constructed to be turned by the hand or foot.
“A rudder to the hinder part of the vessel, which commanded it with the greatest ease, was made very elastic, and might be used for rowing forward. The tiller was within the vessel, at the operator’s right hand, fixed at a right angle on an iron rod which passed through the vessel.
“A compass marked with phosphorus directed the course above and under water.
“The internal shape of the vessel, in every possible section of it, verged toward an ellipsis, as near as the design would allow; but every horizontal section, although elliptical, was yet as near to a circle as could be admitted.
“The body of the vessel was made exceedingly strong; a firm piece of wood was framed parallel to the conjugate diameter, to prevent the sides from yielding to the great pressure of the incumbent water in a deep immersion. This piece of wood was also a seat for the operator.
“Every opening was well secured. The pumps had two sets of valves. The aperture at the bottom for admitting water was covered with a plate perforated full of holes, to receive the water and prevent anything from closing the passage or stopping the valve from shutting. The brass valve might likewise be forced into its place with a screw. The air-pipes had a kind of hollow sphere fixed round the top of each, to secure the air-pipe valves from injury. These hollow spheres were perforated full of holes for the passage of air through the pipes; within the air-pipes were shutters to secure them, should any accident happen to the pipes or the valves on their tops. All the joints were exactly made, and were water-tight.
“Particular attention was given to bring every part necessary to performing the operation, both within and without the vessel, before the operator, so that everything might be found in the dark. Nothing required the operator to turn to the right hand or the left.
“DESCRIPTION OF A MAGAZINE AND ITS APPENDAGES DESIGNED TO BE CONVEYED BY THE SUBMARINE VESSEL TO THE BOTTOM OF A SHIP.
“In the fore part of the brim of the crown of the vessel was a socket, and an iron tube passing through the socket; the tube stood upright, and could slide up and down six inches. At the top of the tube was a wood-screw, fixed by means of a rod, which passed through the tube and screwed the wood-screw fast upon the top of the tube. By pushing the wood-screw up against the bottom of a ship, and turning it at the same time, it would enter the planks. When the wood-screw was firmly fixed, it could be cast off by unscrewing the rod which fastened it upon the top of the tube.