American naval men were naturally impressed by this performance, and also by a series of experiments which were carried out by Mr Glen H. Curtiss, the builder of the biplane which bears his name. Mr Curtiss designed a biplane which would float upon the water on pontoons, and also rise from the surface of the water when it moved forward at a certain speed. Considerable ingenuity was exercised in the construction of this machine. The pontoons upon which it was mounted, and which took the place of ordinary land wheels, were hollow boxes with pointed ends, made out of wood, and sheathed with thin steel. A large pontoon, under the centre of the biplane, bore the greater part of the weight, and a smaller pontoon was set under the front of the machine; while a third pontoon, smaller still, was placed at the extreme forward end of the aeroplane, to tilt it upward when it began to move across the water. First tests with this machine were entirely successful. When forced forward by its propeller, at a speed of thirty miles an hour, the hydro-aeroplane skimmed along with only its main pontoon on the water. Then, at a slight acceleration, it rose easily into the air, and flew off. Descents upon the surface of the water were made with equal facility. [Illustration: MOTOR TRANSPORT. Photo, M. Branger. This picture shows how a Breguet military biplane, with its main-planes folded by the sides of its body, can be towed from point to point behind a motor-lorry.] After satisfying himself that his machine answered expectations, Curtiss carried out an instructive test in conjunction with an American battleship. Flying from a point on shore, he made a successful descent upon the water close beside the vessel. Then his machine was hoisted on board, by means of special tackle. To complete the test, the biplane was subsequently lowered into the water again; and Curtiss rose without difficulty, flying back to the shore. The objection to such a scheme as this, of course, would lie in the probable roughness of the sea under many conditions of work. Were a high sea running, it is generally admitted that an aeroplane could not possibly rise from, or land upon, the surface of the water. Therefore, the sound plan, at any rate on the high seas, would seem to be for an air-scout to be launched from the deck of a ship. An aeroplane on pontoons should, however, find many uses for coastal work. It could, for example, be housed in a shed on the water. It could then leave harbour on a reconnoitring flight, and return again, when alighting, to the smooth water inside the harbour. An involuntary descent, when over the water, would not cause it injury.