This Voisin biplane differed from the Wrights’ in that it followed the box-kite principle. It had a box-kite tail to which the rudders were mounted, while the wings had vertical partitions and the plane had no lateral controls, with the result that it could not fly in any kind of a wind without coming to grief. The first machine had a 50 horse-power Antoinette engine and the latter ones a 40 horse-power Vivinus—an ordinary automobile engine, heavy but reliable. In 1909 the famous Gnome rotary engine appeared. It had 11 cylinders set like the spokes of a wheel; one was fitted to a Voisin biplane by M. Louis Paulhan. There were several innovations on this machine. The under-carriage and tail-booms and much of the understructure was made of steel tubing. Its greatest contribution to the modern aeroplane was the steering-wheel. This was operated by a rod or joy stick, which ran from the front elevator to a wheel in front of the pilot which was pushed forward to force the nose of the machine down, and pulled back to force it up. This made steering much easier. The rudders were worked by wires leading to a pivoted bar on which the pilot’s feet rested. Pushing the right foot steered to the right, pushing the left foot steered to the left—which was also a very natural motion. This method of construction has been maintained to this day on all machines. The Voisin was the first “pusher” type of machine with single propeller in the rear of the engine and the plane. The Voisin was always heavy, but in 1915 it was built in large numbers for bombing purposes because the forward nacelle or nest which held the observer and gunner afforded such an unobstructed range of vision for the observer. To M. Louis Bleriot goes the honor of first constructing monoplanes and of putting the engine in the nose of the machine with a tractor screw in front of it. He also first designed the fish-shaped, or stream-line, body, with the tail and elevator planes horizontally and the vertical rudder fixed at the rear end of the fuselage. This was the first successful tractor aeroplane with the propeller in front. In 1909 M. Bleriot came to the fore with his type X1 machine, the prototype of all successful monoplanes. In this he incorporated the Wright idea of warping the wings to give lateral control, and so produced the first monoplane to be controllable in all directions. With this type of machine, equipped with a 28 horse-power three-cylinder Anzani air-cooled engine, M. Bleriot himself flew over the Channel on July 25, 1909. His type X1 model, with a few structural details, was the first to loop the loop regularly in 1912. After 1909, when fitted with Gnome or Le Rhone rotary engines, the performance of the machine was greatly improved. Since the Bleriot under-carriage, excellent for its purpose, could not be made so as to be pushed rapidly through the air, it was abandoned.