Up to this point an attempt has been made to give some idea of the progress that was made during the eleven years that had elapsed since the days of the Wrights’ first flights. Much advance had been made and aeroplanes had settled down, superficially at any rate, into more or less standardised forms in three main types--tractor monoplanes, tractor biplanes, and pusher biplanes. Through the application of the results of experiments with models in wind tunnels to full-scale machines, considerable improvements had been made in the design of wing sections, which had greatly increased the efficiency of aeroplanes by raising the amount of ‘lift’ obtained from the wing compared with the ‘drag’ (or resistance to forward motion) which the same wing would cause. In the same way the shape of bodies, interplane struts, etc., had been improved to be of better stream-line shape, for the further reduction of resistance; while the problems of stability were beginning to be tolerably well understood. Records (for what they are worth) stood at 21,000 feet as far as height was concerned, 126 miles per hour for speed, and 24 hours duration. That there was considerable room for development is, however, evidenced by a statement made by the late B. C. Hucks (the famous pilot) in the course of an address delivered before the Royal Aeronautical Society in July, 1914. ‘I consider,’ he said, ‘that the present day standard of flying is due far more to the improvement in piloting than to the improvement in machines.... I consider those (early 1914) machines are only slight improvements on the machines of three years ago, and yet they are put through evolutions which, at that time, were not even dreamed of. I can take a good example of the way improvement in piloting has outdistanced improvement in machines--in the case of myself, my ‘looping’ Blériot. Most of you know that there is very little difference between that machine and the 50 horse-power Blériot of three years ago.’ This statement was, of course, to some extent an exaggeration and was by no means agreed with by designers, but there was at the same time a germ of truth in it. There is at any rate little doubt that the theory and practice of aeroplane design made far greater strides towards becoming an exact science during the four years of War than it had done during the six or seven years preceding it. It is impossible in the space at disposal to treat of this development even with the meagre amount of detail that has been possible while covering the ‘settling down’ period from 1911 to 1914, and it is proposed, therefore, to indicate the improvements by sketching briefly the more noticeable difference in various respects between the average machine of 1914 and a similar machine of 1918.