Before beginning the main subject of my lecture, the Society may perhaps wish me to refer to some of the outstanding events of the year.

The honour of the first flight round the world has fallen to the countrymen of Wilbur and Orville Wright, and well have they deserved it. We can realise to the full the courage, endurance and skill that they brought to their task; and we can share to the full the disappointment of those of their own party, and of their friendly French and British competitors, who had the misfortune to fall by the way.

The flights round Australia, though less spectacular, and covering less distance, are perhaps equally worthy of recognition. With practically no organisation, complete reliance had to be placed on the aircraft and engines, as well as on the pilots; there, was no possibility of effecting any but quite minor replacements.

For many years the claim has been put forward that the Royal Aeronautical Society is the oldest aeronautical body in the world through its unbroken existence since its inception on January 12th, 1866. This is a proud title—though not perhaps so proud as that of being the most active and up-to-date—which it has interested the writer to examine in the light of various documents bearing on the history of similar French societies which he possesses in his own collection of early aeronautical literature or has found in the admirably complete historical library at 7, Albemarle Street. In the hope that these researches may prove of interest to others, and of assistance to future historians, he has set down the results here in the form of notes on the various French societies, grouped under the four heads into which they seem to fall, the authorities for various statements made being inserted in brackets.

In surveying the mass of aerodynamic data presented to the designer of aeroplanes, one is struck by the fact that so much attention has been devoted to quantitative measurements upon bodies in a flow of air, so little to the equally important qualitative measurements. It is known that any body subjected to a flow of air is the means of creating eddies, yet relatively little attention has been given to the study of these eddies. Possibly the assumption has been that such eddies are of little importance since in the case of the aeroplane thev are left behind the body that is causing them and so cannot exert a secondary effect upon it. In fact, an aeroplane in flight is the means of creating a vast number of whirls and eddies in the air, the majority of which are left harmlessly astern, some of which react upon its own structure. Of these whirls and eddies practically nothing is known. Indeed, they are so little considered that it comes almost as a surprise to a practical designer to see the vast disturbances that become evident behind an aeroplane “ skywriting.”