A The bow anchor,
B The plunging flyers communicating by two angle wheels to the insides;
C The bow cable, its windlass Slides backwards and forwards on a square axis and lays the cable in regular coils;
D A small safety pump to drive the water out of the balancing chest G; suppose this pump one inch diameter, a column of water one inch diameter and 300 feet high would weigh about 150 pounds; hence one Man with a lever of three to one; could work such a pump under a pressure of 300 feet and rendering the Vessel lighter than her volume of water, could mount from that or even a greater depth to the surface;
E and F a pipe and cock to let the water into the balancing chest G;
G The balancing chest of a capacity to receive from three to five hundred weight of water, when the outer chambers are full, the Vessel being still from three to five hundred pounds lighter than water; Water is then let into the balancing chest correctly to such a weight that the flyers or plunging anchor can hold her under water;
H A air pipe to let out the Mephitic air; there is a similar one which extends to the stern, and enters a Ventilator Q by which means the air may be renewed in the Vessel;
I A movement to work the rudder while under water; on going to plunge the man who steers must take the helm off, this should always be his first act least he should forget it,
K The windlass of the plunging anchor sliding like that at the bow;
J The crank of the stern flyers; of the pumps, and of the plunging anchor; all these movements to be performed at pleasure by sliding the little wheels N and O in & our of gear;