The mistake that he made, which was exposed to him by his son, set him out on a new line of thought, and showed him vaguely where his error was, though not the nature of it. And the discovery which he made at the outset was a startling one, and it may cause some astonishment to the player of to-day who will reflect upon it for a moment. The steadiest, most constant, and most persistent force with which we are generally acquainted is the force of gravity. It is always there; it acts unceasingly upon everything. To defeat gravity, therefore, is almost for a while to suspend the working of Nature. Suddenly it burst upon the mind of the Professor that the golf ball was made as it were to defeat gravity, and so in a sense it does. He found this out by observing the time of flight of the ball, and discovering that it was nearly twice as long as it ought to be, if gravity had free and unfettered play. This is to say, that if gravity were allowed to act in the usual way on the ball from start to finish, as it acts on other things, it was quite inevitable by all the laws of nature and science that a drive of 200 yards would be completed in three and a half seconds. If a man threw a ball so as to describe as nearly as possible the same trajectory as a golf ball, and to stop at the same spot, it would only take three and a half seconds. But the golf ball takes six and a half seconds! Somehow or other it was clear that gravity was being beaten all the way. If it were not so, it would be impossible for the golf ball to remain in the air so long while it was accomplishing such a short flight. That was the great mystery that the professor had to solve, and he solved it at last. It may be said here, in passing, and will be more fully explained another time, that he found out that it was due to the rotation given to the ball by the club, and the nature of the stroke when it was struck from the tee, a rotation which in many ways was responsible for some most extraordinary happenings; all of which the golfer will be a much wiser man for having knowledge of. But before he could go thoroughly into the mystery of this rotation he had to make many other preliminary investigations, and some of the results of these may be quoted.