It is indeed an honour and a pleasure to join with you in honouring the memory of one of the great pioneers in British aviation. When I read the story of Captain Frank Barnwell's life so ably presented by Major Bulman in the first of these lectures, I was struck by the indomitable spirit of a man who, at the age of 57, was still determined to flight test his own new design. It is the same type of spirit that sustained Alan Shepard through a decade of physical adversity to reach the moon at the age of 47 and perform on its surface with all of the vigour this mission required. It is this type of human spirit that has made all of the fabulous technical achievements possible, and it is this type of spirit that is an essential ingredient for the continued assault on the great unknowns that lie in murky darkness all along the frontiers of man's knowledge of himself and his universe.