May I thank the Society for the immense compliment it has paid me tonight by the award of the Society's Gold Medal. Earlier this year I was prevailed upon by Council to prepare the Wright Brothers Lecture. This is an occupational hazard of the Director, RAE, and has led to a situation—unique in my experience—in which the Society has presented the Medal and then within a few minutes asked the recipient to stand up and earn it. I am not at all optimistic about the outcome—but will do my best.