There is a type of aeroplane which will be carried to sea when a fleet sails, stowed in sections within the hull of a transport ship. This machine--a light, high-speed craft--will be assembled upon the deck of its parent ship, and launched into the air by special mechanism, as there is not room for a machine to run upon wheels, and leave the ship’s deck as it might do upon land; the vessel, besides, might be rolling in a high sea. In some cases a platform is built upon the deck, either at the bow or stern, and along this the aircraft moves, so as to gain speed for its planes to lift. In one device, seen in Fig. 87, the machine is mounted upon a light wheeled cradle, and this is placed upon the starting-rail. Then, driven by its propeller, the plane runs forward upon the cradle till it reaches the end of the rail, when it glides into the air, the cradle falling from it and dropping into the sea, from which it is retrieved and drawn back on board the ship. By another method, shown in Fig. 88, the sea-plane is launched from a cable suspended between two masts, and can come to rest upon the cable again after a flight has been made. The machine is hung upon the cable prior to making an ascent; then the pilot starts his engine, and as his machine glides forward along the cable he releases a catch and soars into the air. Upon returning he flies beneath the cable, and makes his craft rise until the “V”-shaped apparatus above his head is caught by the cable and the catch becomes operative; then he stops his motor, and his craft hangs from the cable as it did before. [Illustration: FIG. 87.--Launching sea-planes from a ship’s deck. The sea-plane (A.) is seen taking flight, having glided upon its cradle along the platform (B.). The cradle (C.) is just falling away below the aircraft’s hull.] [Illustration: A. Sea-plane; B.B. Cable; C. The “V”-shaped apparatus which guides the cable into the clip (D.) and so suspends the machine from the wire. FIG. 88.--Launching a sea-plane from a wire.] A flying scout, operating with a fleet at sea and rising from the deck of a ship, would be of very distinct value. When approaching an enemy he would be sent aloft to reconnoitre, and would locate hostile craft before men could see them from the ships below. The utility of such a scout is proved by the lessons of history. On one occasion, for instance--it was in 1805--Nelson was waiting to intercept a French fleet at Toulon. But they managed to steal out unobserved, and Nelson chased them to the West Indies before he caught them. If he had had an aeroplane to send up and keep watch, he would not have missed his enemy. The air-scouts of a fleet would note also the approach of airships, and could spy upon harbours or fortifications when an attack was being made upon them from the sea.