Two years before the publication of Penaud’s patent Thomas Moy experimented at the Crystal Palace with a twin-propelled aeroplane, steam driven, which seems to have failed mainly because the internal combustion engine had not yet come to give sufficient power for weight. Moy anchored his machine to a pole running on a prepared circular track; his engine weighed 80 lbs. and, developing only three horse-power, gave him a speed of 12 miles an hour. He himself estimated that the machine would not rise until he could get a speed of 35 miles an hour, and his estimate was correct. Two six-bladed propellers were placed side by side between the two main planes of the machine, which was supported on a triangular wheeled undercarriage and steered by fairly conventional tail planes. Moy realised that he could not get sufficient power to achieve flight, but he went on experimenting in various directions, and left much data concerning his experiments which has not yet been deemed worthy of publication, but which still contains a mass of information that is of practical utility, embodying as it does a vast amount of painstaking work. Penaud and Moy were followed by Goupil, a Frenchman, who, in place of attempting to fit a motor to an aeroplane, experimented by making the wind his motor. He anchored his machine to the ground, allowing it two feet of lift, and merely waited for a wind to come along and lift it. The machine was stream lined, and the wings, curving as in the early German patterns of war aeroplanes, gave a total lifting surface of about 290 sq. ft. Anchored to the ground and facing a wind of 19 feet per second, Goupil’s machine lifted its own weight and that of two men as well to the limit of its anchorage. Although this took place as late as 1883 the inventor went no further in practical work. He published a book, however, entitled _La Locomotion Aérienne_, which is still of great importance, more especially on the subject of inherent stability. In 1884 came the first patents of Horatio Phillips, whose work lay mainly in the direction of investigation into the curvature of plane surfaces, with a view to obtaining the greatest amount of support. Phillips was one of the first to treat the problem of curvature of planes as a matter for scientific experiment, and, great as has been the development of the driven plane in the 36 years that have passed since he began, there is still room for investigation into the subject which he studied so persistently and with such valuable result.