We should like to preface our essay on the subject of spinning by mentioning the circumstances under which our investigations were carried out and the sources of our information. The Panel of the Aeronautical Research Committee which has been appointed to deal with all questions connected with the stability and control of aeroplanes was requested in 1924 to consider the urgent problems connected with the alarming accidents due to certain machines failing to retover from a spin. After the issue of a preliminary report on the situation by the Panel, the writers of this paper were asked to go into the whole question as far as existing information from full-scale and wind tunnel experiments would permit. We have had ready access to all available data, coming chiefly from Farnborough on the full-scale side, and from the N.P.L. on the model side.

In addressing you, I wish to express, first of all, my sincerest thanks for the honour you have bestowed upon me to speak before the Royal Aeronautical Society of London about the “ Development of the Commercial Air Traffic in Germany.” It is with great pleasure I take the opportunity of giving you information about our ideas and intentions, and I hope that my explanations will assist in improving the understanding of our mutual needs in the service of the world's commercial air traffic. The Chairman of the Royal Aeronautical Society sent me a number of particular questions, and my speech, for this reason, goes in some instances very much into details which otherwise I would not have mentioned.

If I now ask you for your attention to tell you something about the air traffic in Germany, I may mention that I have been with the management of German air traffic companies since 1919.