As always happens in the many-minded development of a complex invention, the general exhibition and use of the aëroplane led toward uniformity of design. This became particularly noticeable during the world-wide demonstrations of 1909 and 1910. Whatever predilection the inventor might have for his own devices, he would rather cast them aside than lose at the tournament and in the market. Without a monopoly of the flying art, he could ill afford to retain too affectionately his own second-rate device in competition with a rival having a more effective one. Accordingly there was a judicious and general adoption of those devices which had proved best in practice, from whatever lowly intellect they had emanated. Thus there was a marked tendency to the general use of starting wheels, landing skids, large warping surfaces, and, in racing machines, to the stream line concentration of the load, and the severe elimination of resistance. A few examples will illustrate this tendency to choose the most practical devices from the world’s general stock. The Wright brothers, who, following Maxim, had been ardent votaries of the forward horizontal rudder, discarded this in 1910 for the elastic rear horizontal rudder introduced by Etrich. At the same time they abandoned the antiquated catapult introduced by Langley, and adopted the combination of wheels and skids introduced by Farman. In their racing machine they no longer placed the aviator beside his engine, presenting a broad front to the wind, but, like Curtiss and foreign designers, they placed the driver and power plant in line, to diminish the atmospheric resistance. These manifold and timely improvements indicate clearly the advantages to mankind of an “open door” in a crescent art. But if the Wrights adopted the most successful devices of their neighbors, these in turn were not slow to reciprocate that policy. There was ample recognition of the merit of the combination of warping sustainers and double rudder proposed by scientific men before the advent of power aëroplanes, and so admirably employed by the Wrights and Prof. Montgomery in their early coasting flights. The warping wing was quite generally used on monoplanes in 1910; not to mention the _ailerons_, which frequently were an adaptation of the same principle.