and down; he could steer right or left by moving the vertical rudder. He had no ailerons nor wing-warping mechanism, but for lateral balance depended on the dihedral angle of the wings and upon suitable movements of his weight or of the vertical rudder. After the adjustments for actual flight had been made in the Curtiss factory, according to the minute descriptions contained in the Langley Memoir on Mechanical Flight, the aeroplane was taken to the shore of Lake Keuka, beside the Curtiss hangars, and assembled for launching. On a clear morning (May 28th) and in a mild breeze, the craft was lifted on to the water by a dozen men and set going, with Mr Curtiss at the steering wheel, esconced in the little boat-shaped car under the forward part of the frame. The four-winged craft, pointed somewhat across the wind, went skimming over the wavelets, then automatically headed into the wind, rose in level poise, soared gracefully for 150 feet, and landed softly on the water near the shore. Mr Curtiss asserted that he could have flown farther, but, being unused to the machine, imagined that the left wings had more resistance than the right. The truth is that the aeroplane was perfectly balanced in wing resistance, but turned on the water like a weather vane, owing to the lateral pressure on its big rear rudder. Hence in future experiments this rudder was made turnable about a vertical axis, as well as about the horizontal axis used by Langley. Henceforth the little vertical rudder under the frame was kept fixed and inactive.[7] That the Langley aeroplane was subsequently fitted with an 80 horse-power Curtiss engine and successfully flown is of little interest in such a record as this, except for the fact that with the weight nearly doubled by the new engine and accessories the machine flew successfully, and demonstrated the perfection of Langley’s design by standing the strain. The point that is of most importance is that the design itself proved a success and fully vindicated Langley’s work. At the same time, it would be unjust to pass by the fact of the flight without according to Curtiss due recognition of the way in which he paid tribute to the genius of the pioneer by these experiments. XIX THE WAR PERIOD--I Full record of aeronautical progress and of the accomplishments of pilots in the years of the War would demand not merely a volume, but a complete library, and even then it would be barely possible to pay full tribute to the heroism of pilots of the war period. There are names connected with that period of which the glory will not fade, names such as Bishop, Guynemer, Boelcke, Ball, Fonck, Immelmann, and many others that spring to mind as one recalls the ‘Aces’ of the period. In addition to the pilots, there is the stupendous development of the machines--stupendous when the length of the period in which it was achieved is considered.