Before proceeding, I wish to say that I much appreciate the invitation to present this paper to your Society. The science of aeronautics has evolved at a great pace, and typifies what can be done with applied science, and the tangible results are so apparent that it would be superfluous to discuss them. It would .appear to me that the rapidity with which the efficiency has increased is due to the whole-hearted collaboration of the different branches of applied science and engineering, the honours being shared, after giving first place to the sporting instinct of the early flyer, by the physicist, the engineer, and the metallurgist. You will notice that my modesty places the metallurgist last. It is quite a confession to make, but it is a fact, nevertheless, that I accepted with pleasure your invitation to give this paper, principally because I have always taken a keen interest in the metallurgical side of aeronautics.

It may seem rather presumptuous for one who does not himself fly to discuss, the dangers that may be met with in the air as though a landsman who had crossed the Channel a few times were to write on the navigation of a ship across the ocean. At the same time, it may be of some use to point out certain conditions of the atmosphere which seem to me to constitute dangers, although I may be mistaken in my estimate of some of these, and would welcome any information from pilots bearing on the subject. In fact, my paper is meant to elicit information rather than to give it.

In addressing myself to the members of the Aeronautical Society of Great: Britain, the oldest institution of its kind in the world, I have to bear in mind that a section only of that membership is composed of designers of internal combustion engines. Therefore I have striven to make my remarks this evening as intelligible as possible to those who have not had such training.