A rudder, hung to the hinder part of the vessel, commanded it with the greatest ease. The rudder was made very elastic, and might be used for rowing forward. Its tiller was within the vessel, at the operator’s right hand, fixed at a right angle on an iron rod which passed through the side of the vessel; the rod had a crank on its outside end which commanded the rudder by means of a rod extending from the end of the crank to a kind of tiller fixed upon the left hand of the rudder. Raising and depressing the first-mentioned tiller turned the rudder as the same required. A compass marked with phosphorus directed the course, both above and under the water, and a line and lead founded the depth when necessary. The internal shape of the vessel, in every possible section of it, verged towards an ellipsis, as near as the design would allow, but every horizontal section, although elliptical, yet as near to a circle as could be admitted. The body of the vessel was made exceedingly strong, and to strengthen it as much as possible 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 choking the passage or stopping the valve from shutting. The brass valve might likewise be forced into its place with a screw if necessary. 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 the 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. [Illustration: BUSHNELL’S SUBMARINE ] Wherever the external apparatus passed through the body of the vessel the joints were round and formed by brass pipes, which were driven into the wood of the vessel, the holes through the pipes were very exactly made, and the iron rods which passed through them were turned in a lathe to fit them; the joints were also kept full of oil to prevent rust and leaking. Particular attention was given to bring every part necessary for performing the operations, both within and without the vessel, before the operator, and as conveniently as could be devised, so that everything might be found in the dark except the water-gauge and the compass, which were visible by the light of the phosphorus, and nothing required the operator to turn to the right hand or to the left to perform anything necessary.