A steamer on wheels, but intended to travel on the water, was invented a few years since by a Frenchman named Bazin. He constructed a model, which worked well and was on the scale of one-twenty-fifth of the liner he hoped to see built some day. The model consisted of four pairs of hollow wheels or discs, each wheel being in appearance like two immense soup-plates set face to face and set on edge. These wheels were caused to revolve, thereby reducing the friction of the water to a minimum, and the vessel was propelled by a screw. The decks, being built on a framework over the axles, had space for ample accommodation, and in order that the speed of the ship should not suffer it was intended to carry no cargo. A vessel on this plan was constructed and launched on the Seine. The platform was 126 feet long by about 40 feet wide, and each wheel was about 32 feet in diameter and about 10 feet at its greatest width. The total weight of the boat was about 280 tons. The boat proved her utility when tried. The inventor estimated that an ocean-going liner constructed on this system would easily cross the Atlantic at a rate of thirty knots an hour. It is impossible to say what the development of the steam-ship will be in the future. The piston engine has probably reached its utmost development, or very nearly so, and much more in that direction is not to be expected. Naval architects are already considering whether the existing lines of the steam-ship are the best for speed, and a design has been brought out for a steamer constructed on what are known as tetrahedral lines. There has recently been described in the _Scientific American_ a vessel, a model of which has been constructed, designed upon this tetrahedral principle. It is contended that this form for ships offers less resistance than any, and that by it alone can the greatest attainable speed at sea be reached. Yarrow boilers with Schultz turbines are recommended for vessels of this type. A proposal for fast Atlantic travelling, which has not gone beyond the paper stage, is that three long narrow hulls should be built parallel to each other and supporting the main body of the hull. The inventor claims that the method would enable a greater speed to be attained than by any existing liner, and at a less cost; but readers who have followed the development of the steam-ship will recollect that this suggestion provides a curious parallel to the experiments of Patrick Miller with his triple-hulled boats in the eighteenth century. Few, however, will doubt that, great as have been the changes in shipbuilding and steam-propulsion during the last hundred years, there will be changes as great in the present century. [Illustration: C. WATSON’S DOCK AT ROTHERHITHE, LIFTING H.M. BRIG “MERCURY.” _From Watson’s Specification.--A.D. 1785._ THE BERMUDA FLOATING DOCK, LIFTING A 15,000-TON IRONCLAD OF THE “MAJESTIC” CLASS. _From the Contract Drawings.--A.D. 1900._