As a guest of the Royal Aeronautical Society, I wish first to express my sincere appreciation of the opportunity to join those others who have appeared before you in years past to present the Wilbur Wright Memorial Lectures. To those of us who are primarily concerned with the scientific aspects of aviation this continuing series of lectures, now nearly as old as the art of human flight itself, is the finest tribute that could be offered in honour of the accomplishments of the Wright brothers. It is on this account that I feel most sincerely the honour and privilege that has been granted me through your invitation to present the Twenty-seventh Wilbur Wright Memorial Lecture.

The title—“ Some Modern Methods of Research in the Problems of Flight ”— is, I confess, somewhat ambiguous. At the time it was selected, some months ago, several investigations then in progress gave promise of results sufficientlyinteresting to be included.

Our first phase of activity, at the Guidonia supersonic wind tunnel, was devoted to studying and designing the necessary apparatus for carrying out systematic research. (See Captain Gasperi's paper, read before the Lilienthal Congress in 1937-) This apparatus consisted principally of:—

1. (1) A series of transformer jets, to create the requisite speeds in the test chamber;

2. (2) A balance, to determine the forces exercised by aerodynamic phenomena upon the objects under test;

3. (3) The striometric and interferometric apparatus.

The initial study was long and laborious; since we lacked the great help furnished by previous research, which is nearly always forthcoming in similar studies, we had to proceed by means of successive experiments until the apparatus took its final shape. Eventually we evolved a series of jets, a balance and an optical installation which we hope are permanent. These, however, being still under construction, have not yet been tested.