The development of aviation, particularly since the War, has led to a growing demand for information on various aspects of meteorological science as applied to flying, and the investigation of the problems thus raised has helped considerably towards increasing our knowledge of the atmosphere and its mechanism.In so far as the subject of wind structure is concerned, attention has been concentrated mainly on the accumulation and interpretation of data regarding the average direction and speed of the wind currents at different levels in various parts of the world.The horizontal variations of wind and the vertical currents which disturb the regular flow of air have received, in comparison, little consideration. The latter aspect of the subject is of paramount importance in connection with the problem of soaring flight; it is also related to the more general question of the stability of aircraft.

The work for the development of air traffic in Europe into a generally recognised means of communication in conjunction with railways and steamships,has hitherto mainly been done through the conveyance of passengers and goods. Mail has certainly been carried by the aeroplanes, but as a rule only in small quantities. As managing director of the Aerotransport Company, the Swedish Air Line, I have seen this development with a certain amount of worry and distrust, and submitted therefore to the International Air Traffic Association a suggestion lor organising, at the earliest possible moment, a general European air mail net, mainly for night traffic. My suggestion was dealt with by a Committee appointed at the Iata's last session in Antwerp, and the suggestion was discussed also at the Postal Congress which was held at Brussels in October,1930.

I realise that the question of establishing air mail conveyance between London and the various parts of the Empire is of great importance from a British point of view, but as this object has nothing to do with the aims for which I am working, I shall not touch upon it to—day.

The terms “ Flying—boat ” and “ Seaplane ” convey to our minds two distinct types of marine aircraft, which have many points in common and yet many points not in common, and together they cover such a vast amount of subject matter,that it is only possible to deal with a limited number of aspects in this paper.