The hull of the vessel is mounted on three wheels. Of these E is the rudder, for surface steering, and is also the guiding wheel when the vessel is running on the sea bottom; and C is one of the supporting and driving wheels, of which there are two, one on each side. BB are two anchor weights, each weighing 1,000 pounds, attached to cables, and capable of being hauled up or lowered by a drum and mechanism within the boat: 0000 are water-ballast compartments contained within the boat; H is the diver’s compartment, situated forward, with an exit door opening outward in the bottom; while G is an airlock. When it is desired to submerge the vessel, the anchor weights BB are first lowered to the bottom; water is then allowed to enter the water-ballast compartments until her buoyancy is less than the weight of the two anchors, say 1,500 lbs.; the cables connecting with the weights are then wound in, and the vessel is thus hauled to the bottom, until she comes to rest on her three wheels. The weights are then hauled into their pockets in the keel, and it is evident that she is resting on the wheels with a weight equal to the difference between her buoyancy with the weights at the bottom, and the weights in their pockets, or 500 lbs. Now this weight may be increased or diminished as we please, either by admitting more water into the ballast tanks or by pumping some out. Thus it will be seen that we have perfect control of the vessel in submerging her, as we may haul her down as fast or as slow as we please, and by having her rest in the bottom with sufficient weight to prevent the currents from moving her out of the course, we may start up our propeller or driving-wheels and drive her at will over the bottom, the same as a tricycle is propelled on the surface of the earth in the upper air. In muddy bottoms, we rest with a weight not much over 100 lbs.; while on hard bottoms, or where there are strong currents, we sometimes rest on the wheels with a weight of from 1,000 to 1,500 lbs. Thus the effect of currents and wave motion, and the maintenance of trim and equilibrium are not factors in the successful navigation of the vessel; in fact, navigation becomes surer on the surface, as one is travelling in a medium which does not constantly change like the surface water from the effects of winds, waves, and currents. When the divers desire to leave the vessel they go into the diver’s compartment, located in the forward portion of the ship, and close the door communicating with the living quarters. This door closes on rubber packing, and is air-tight. Air is then admitted into the compartment from compressed-air reservoirs, until the pressure of air equals that of the surrounding water. The bottom door may then be opened, and no water will come into the boat, as the pressure of air contained within the compartment offers an invisible barrier to its entrance, and the divers may pass in and out as frequently as they please.