At the bottom of the swing, therefore, the club head is, or should be, moving in a straight line. Probably it is when the greatest acceleration in the velocity of the club, and the strongest wrist action in the swing of the arms occur in this straight portion of the stroke, that the follow-through is most efficacious.
For one who essays to explain the mystery of golf, this is a very marvellous statement. Probably at no portion whatever of the golf stroke is the club head proceeding in a straight line. It may be taken for an absolutely settled fact that it is always proceeding in an arc. Also it is quite clear that the author is making the sad mistake, which has been made by so many other people, of thinking that the wrist action is most in evidence immediately before and after the period of impact. Most of the leading golfers fall into the error of stating that cut is obtained by something which is done by the wrists at the moment of impact, but this is unquestionably an error. I have dealt with that already in other places so fully that I think that it will not be necessary for me to do more here than to state that in all good shots the cut is decided upon practically the moment the club begins its downward journey, for the amount of cut which is administered to any ball depends entirely upon the speed, and the angle at which the club head passes across the intended line of flight of the ball, provided always, of course, that the club is properly applied.
CHAPTER X
THE FLIGHT OF THE GOLF BALL
The flight of the ball, and particularly of the golf ball, exercises a strange fascination for many people to whom the phenomena of flight exhibited by a spinning ball travelling through the air, are not of the slightest practical importance. That is to say, there is an immense number of people who take merely a scientific, and one might almost say an artistic interest in the effects produced by the combined influence of spin and propulsion. Scientific men have been for many years well aware of the causes which produce the swerve of a ball in the air. By swerve I mean, of course, a curve in the flight of the ball which is due to other causes than gravitation, and in the word swerve I do not include the drift of a ball which has been perfectly cleanly hit, but which, in the course of its carry, has been influenced by a cross wind. This does not legitimately come under the heading of swerve. It is more correctly described as drift, and will be dealt with in due course.
In the Badminton Magazine of March 1896, the late Professor Tait published an article on "Long Driving." Professor Tait was a practical golfer and a very learned and scientific man. He proved most clearly that a golf ball could not be driven beyond a certain distance. He proved this absolutely and conclusively by mathematics, but, so the story runs, his son, the famous Freddie Tait, proved next day with his driver, that his father's calculations were entirely wrong, for he is alleged to have driven a golf ball over thirty yards farther than the limit which his learned parent had shown to be obtainable. Naturally, Professor Tait had to reconsider his statements, and he then arrived at the conclusion that there must have been in the drive of his son, which had upset his calculations, some force which he had not taken into consideration. He soon came to the conclusion that this was back-spin, and he dealt with this matter of back-spin, which is a matter of extreme importance to golf, in a most erudite article, which is much too advanced for the ordinary golfer, so I shall content myself here with referring to just a few of the most important points in connection with it. It is necessary that I should, in dealing with the flight of the ball, give those of my readers who are not already acquainted with the simple principles of swerve, some idea of what it is which causes the spinning ball to leave the line of flight that it would have taken if it had been driven practically without spin.
The explanation is very simple. If a ball is proceeding through the air, and spinning, the side which is spinning towards the hole gets more friction than the other side which is spinning away from the hole. It is well known that a projectile seeks the line of least resistance in its passage through the air. It follows that the greater friction on the forward spinning half causes the ball to edge over towards the side which is spinning away from the hole. This, in a very few words, is the whole secret of swerve.
Professor Tait stated in his article that Newton was well aware of this fact some 230 years before the publication of the professor's article, and that he remarked when speaking of a spinning tennis ball with a circular as well as a progressive motion communicated to it by the stroke, "that the parts on that side where the motions conspire must press and beat the contiguous air more violently, and there excite a reluctancy and reaction of the air proportionately greater."