In the engine-car, the floor of which vibrates very slightly with the hum of the motors and the rush of the machine’s speed, stands the driver upon a raised platform. Immediately before him, as the craft rises slantingly, are the outlook windows; and convenient to hand and eye, as he looks first ahead and then back to his controls, are the wheels, levers, dials, and gauges by which he governs all the movements of his swift-flying charge. Bending forward, he moves his steering-wheel; then watches attentively the needle of the compass, which is fitted in an upright stand just before him. Then from the compass dial he turns to a map, which is stretched neatly upon a frame. Again he glances at the compass; then straightens himself and turns to speak to the mechanic. He has now adjusted the craft’s path, and she is flying accurately upon her compass course. After this, with an even, monotonous throb of sound, and a faint clamour from the wind around the hull, the craft rushes upon her way; and while the driver is absorbed upon his platform the mechanic, moving deftly here and there, tends the great, sleepily-humming motors. Already, in the desire to build large, high-powered machines, some remarkable craft have been produced; and one of the most striking is the Sykorsky, a huge and highly successful Russian biplane. This machine has flown to a height of 3000 feet with sixteen passengers, whose combined weight was nearly a ton and a quarter. In its original form the machine had four motors, each developing 100 horse-power, which were mounted on the lower plane upon either side of the hull, one being placed behind the other and all driving independent screws. But the rear engines were afterwards brought alongside the front ones; and now, in its most recent form, the machine employs three motors, giving a total of nearly 1000 horse-power. The craft has a metal hull, and boasts a cabin with windows. The fitting of several motors, a principle tested in this biplane, has been shown to be practical; and it has the obvious advantage that, should one fail while in the air, the other or others will maintain a craft in flight. In such a machine as would fly the Atlantic, for example, it is proposed to fit four motors developing 800 h.p., and to carry a couple of mechanics who would constantly be tending them. Thus, should one engine develop trouble, its repair could be effected without descent, and with no worse result than a temporary fall in speed. In Fig. 104 is shown a method by which three Gnome motors may be fitted to a biplane. [Illustration: FIG. 104.--Multiple-engined craft. A. First engine (a 50-h.p. Gnome); B. Second engine (which is on the same shaft, but will run independently); C. Third Gnome engine, also an independent unit; D. Four-bladed propeller (mounted higher than the crank-shaft bearing the engines, and driven by a chain gearing).]