During several years of experimental work with submarine investigating bottom conditions I have travelled many miles in the Chesapeake and Sandy Hook bays, along the Atlantic coast and Long Island Sound, and later in the Gulf of Finland and the Baltic Sea; and it is a fact that cannot be successfully disputed, technically, by any one, that a submarine of the type recommended by the United States Army Board may be taken into any harbor in the world entirely unseen, and remain there, if necessary, for a month at a time, destroying shipping, docks, and war craft deliberately and leisurely, and yet defy discovery. My method of entering harbors or through mine fields consists principally in providing submarine vessels with bottom wheels and other component undisclosed details. When submerged, the vessel is given sufficient negative buoyancy so that she will not be drifted off her course by the currents when resting on the bottom. The vessel is what may be termed a submarine automobile, and it may be navigated over the bottom as readily as an automobile runs on the surface of the earth. The submarine automobile has one great advantage over the surface type in its ability to mount steep grades or go over obstructions, because the vessel is so nearly buoyant that she will mount any obstruction she can get her bow over. My early experience proved to me that a submarine could not be satisfactorily navigated submerged in shallow, rough water by the same method of control as was found to be practical in deeper water, for the reason that the vessel would pump up and down with the rise and fall of the sea. Neither could the vessel lie at rest on the bottom, as the lift of the ground swell in bad weather was sufficient, even with a considerable negative buoyancy, to cause the vessel to pound so badly that the storage battery plates would be destroyed in a few minutes. I therefore suspended the wheels on swinging arms and applied a cushioning cylinder. The hull of the vessel was then free to move up and down, synchronizing with the lift of the ground swell, and at the same time the weight of the wheels kept the submarine close to the bottom and able to keep her position while at rest or to be navigated over the bottom at any speed desired. Most of our Atlantic coast, Long Island, and Chesapeake Bay water-beds are comparatively uniform as to depths. In other countries I have navigated over rocky bottoms filled with giant boulders. A rough bottom limits the speed at which it is advisable to travel, but I have never seen a bottom so rough that it could not be readily navigated.