Up to the time when this motor was introduced, makers had, in designing aeroplane engines, followed very largely upon motor-car design, constructing motors with fixed cylinders, either upright, or in "V" shape, and with their parts lightened wherever possible. Some were water-cooled; others air-cooled. But with both systems, and particularly with the latter, the tendency—owing to the high speeds at which the engines had to turn—was to overheat, and either lose power, or stop altogether. The specially-lightened water-cooling systems which were devised gave a great deal of trouble; and, in the case of air-cooled engines, it was usually found almost impossible to prevent overheating, after the engines had been running for ten minutes or a quarter of an hour. In the case of the "Gnome," the designer struck out in a new line. Instead of making his cylinders fixed, and his crank-shaft revolving, as was the method with other engines, he set his seven cylinders revolving around the crank-shaft. Petrol and oil he fed to the cylinders by way of the stationary hollow crank-shaft. The internal complications of this engine, in the opinion of experts who first saw it, were such that it could not be expected to achieve reliability. But it did, nevertheless; and it ran so well, in fact, that, at the Rheims meeting, Henry Farman remained in the air, while using it, for more than three hours, and won the prize for the longest flight. The advantages of this remarkable engine proved to be many. In the first instance, its method of construction enabled it to be built remarkably light; and the fact that the seven cylinders revolved, generally at a speed of 1000 revolutions a minute, effectually disposed of cooling difficulties. In fact, the engine automatically cooled itself; and its fly-wheel effect, as it flew round, gave a smooth, even thrust to the propeller. From the very day of its first introduction, the "Gnome" motor gained overwhelming success. It represented a piece of mechanism made specially for the work in hand, and not a motor-car engine adapted to aerial purposes. This fact was the secret of its success. As rapidly as they could acquire them, other aeroplane makers fitted "Gnomes" to their machines. It proved all-conquering. Fixed-cylinder engines did not languish completely, however. Some of them were steadily improved, and performed reliable work. But the "Gnome" was then, and is now, regarded as _the_ aeroplane engine. The Farman biplane, being so good a machine in itself, and being equipped, in addition, with so excellent a motor, naturally aroused keen military interest; and it was not long before the inventor received Government orders for his machine. At this time, before the monoplane had assumed the commanding position which it now holds, the Farman biplane certainly represented the premier aeroplane of the day.