M. Bleriot introduced the stick form of control, so that by moving the control stick forward or backward the nose of the machine moved down or up. Pushing the stick to the right forced the right wing down, moving it to the left pushed the left wing down. The rudder was worked by the feet as in the Voisin. Thus a natural movement was given to all the controls and a great step forward was made. THE 1909 AND 1910 AVRO Meanwhile in England Aylwin Verdon Roe was experimenting under strictly limited conditions. In 1908 he had got off the ground in a Canard-type biplane, and in the fall of that year he built a tractor biplane, and in the summer of the next year he had it completed. His engine was a 9 horse-power J. A. P. motorcycle engine, the lowest power which has ever flown an aeroplane. It was also the first successful triplane. In general lines and plan the machine is the prototype of the modern tractor biplanes and triplanes; it had warping wings, tail elevators, and a rudder astern, while the control was by rudder and stick, similar to the Bleriot. This little machine was further developed in 1909 and 1910. Later Mr. Roe abandoned the triplane for the biplane, which he fitted with a Green engine of the vertical-cylinder type, which was the first of its kind installed in an aeroplane. Thereafter the triplane practically disappeared till it was revived by Glenn Curtiss, as well as British, French, and German designers during the war. They are great climbers and attain great speed in flying. The small 1910 Avro, equipped with a V water-cooled engine, was the forerunner of the single-seated fighters of the last days of the war. Because of its fast-climbing ability the 80 horse-power Avro and the Sopwith Snipe were used for the defense of such cities as London and Paris against Zeps and aeroplanes. The large two-seater Avro, with only an 80 horse-power Gnome, flew over 80 miles an hour. As a war-machine early in the conflict it did excellent work bombing. Later, with slightly higher power, it was a very good training-machine. Among two-seated biplanes it marked as great an advance as did the Sopwith Tabloid. Among single-seaters, for the reason that it had been carefully lightened without loss of strength and all details for stream-line had been observed, the same is true. THE FARMAN BROTHERS’ PLANE