It is a great honour for me to speak to such a distinguished and competent audience. Needless to say, I was pleased to receive the invitation from the Royal Aeronautical Society but was also concerned with the responsibility of treating a subject involving dramatic aspects, which require understanding, and the selection of a certain number of events for presenting a reasonably effective picture of the subject.

I know that it will be impossible for me—for lack of ability and also time—to give a full story of these adventures and ventures and 1 apologise for the omissions. In fact I will only briefly mention some of the facts which have more deeply impressed me or in which I have been directly concerned.