My brother and I became seriously interested in the problem of flight in 1899, a little more than 12 years ago. Some three years before this the death of Lilienthal, which was mentioned in the newspapers of that day, had brought the subject to our attention and led us to make some inquiry for books relating to flight. But the only serious books we found were by Professor Marey, and these related to the mechanism of bird flight rather than human flight. As our interest at that time was mere curiosity as to what had been done, we did not pursue the subject further when we failed to find books relating to human flight.

Several years later, while reading a book on ornithology, we became interested in studying the appearance and habits of birds, but it soon occurred to us that the really interesting thing about birds was their power of flight. This was a power which seemed to us almost in contradiction of the laws of nature.