It is strange that although Newton thoroughly understood the theory of swerve he was in the same error as that of Professors Tait and Thomson, namely that it was the "oblique racket," in other words the "loft" that was producing the spin. He said, writing to Oldenburg in 1671, about the Dispersion of Light, "I remembered that I had often seen a tennis ball struck with an oblique racket describe such a curved line."

It is not so much striking anything with an "oblique" instrument that produces spin, although in certain cases that will, of course, assist, as it is the striking of the oblique blow. Even with such a heavily lofted club as the niblick one will never get much backspin unless one plays the stroke designed to produce it.

It is when we get to slicing and pulling, however, that Professor Thomson gets quite out of his depth. At page 12 of his remarkable paper he says: "So far I have been considering under-spin. Let us now illustrate slicing and pulling; in these cases the ball is spinning about a vertical axis."

This statement is very definite and quite wrong. I have already dealt very fully with the flight and run of the slice and the pull in the chapters devoted to those strokes. I have practically nothing to add to these except to say that any one who has had even a very brief experience of golf will know the different characteristics of the flight and run of the pull as set out by me. They will not require any argument to convince them that these entirely dissimilar effects are not produced by the same axis of rotation.

Professor Thomson performed some most ingenious experiments to demonstrate the correctness of his theories about the slice and the pull. He had an electro-magnet and a red hot piece of platinum with a spot of barium oxide on it. "The platinum is connected with an electric battery which causes negatively electrified particles to fly off the barium and travel down the glass tube in which the platinum strip is contained; nearly all the air has been exhausted from this tube. These particles are luminous, so that the path they take is very easily observed."

These particles, I may say, take in Professor Thomson's mind the place of golf balls, and, by means of his electro-magnet he proceeds to show us exactly what golf balls when pulled or sliced do, but unfortunately for him Professor Thomson is wrong in his theory and he is starting out to make his "particles" do what he wants them to do, which in this case, is something that neither a pulled nor a sliced ball ever does.

At the beginning of Professor Thomson's paper he says: "I shall not attempt to deal with the many important questions which arise when we consider the impact of the club, but confine myself to the consideration of the flight of the ball after it has left the club."

If Professor Thomson had kept to this line of action it would have prevented him from making a very amusing error. He says: "I have not time for more than a few words, as to how the ball acquires the spin from the club, but if you grasp the principle that the action between the club and the ball depends only on their relative motion, and that it is the same whether we have the ball fixed and move the club against it, or have the club fixed and project the ball against it, the main features are very easily understood."

I am afraid that not many of my readers will be able to "grasp the principle" here set out. There is herein no reflection on their mental capacity, but it seems to me that there is a very striking difference in the two propositions so hurriedly set forth by Professor Thomson. If we have the club fixed and project the ball against it we know that the ball will rebound from the club, but if we have the ball fixed and move the club against it, nothing that bears any colorable imitation of golf takes place, unless we move the club fast enough when we should simply smash it- and at least set up some similarity to the real game.

This really is extreme looseness of expression for so weighty a matter! I know quite well what Professor Thomson means to say, but I have not to deal with that, and even what he means to say is wrong. In the meantime I have only to consider "a new dynamics" of how to drive the fixed ball!

I must pass over a good deal that Professor Thomson has to say and come to the rock on which Professor Tait and, following him, Professor Thomson have split. Professor Thomson says: "Suppose Fig. 27 represents the section of the head of a lofted club moving horizontally forward from right to left, the effect of the impact will be the same as if the club were at rest and the ball were shot against it horizontally from left to right. Evidently, however, in this case the ball would tend to roll up the face, and would thus get spin about a horizontal axis in the direction shown in the figure; this is under-spin and produces the upward force which tends to increase the carry of the ball."

This really is an amazing error for a famous physicist to make nowadays. Let us consider that the club he is speaking of is a driver. I have no hesitation in saying that the loft of a driver is practically innocent of having anything to do with producing backspin. The function of that loft is to lift the ball. The beneficial backspin of golf is always obtained by a downward glancing blow, and moreover by a blow that is moving in an arc and not in a straight line, although, of course, when the blow is delivered the force is applied in one direction.

Professor Thomson errs grievously in showing the stroke proceeding in a straight line. This rarely if ever happens in golf. The stroke is upward or downward, far more often upward than downward; for scarcely any one properly trusts the loft of the club to do its part, a want of confidence in the club, I may repeat, that is wholly undeserved. This upward hit kills on the instant any approach to backspin the club might otherwise communicate to the ball for it tends to put the loft of the face at a right angle to the initial line of flight of the ball, thus destroying any obliquity in the impact. Even Professor Tait recognized this important point although he did not see the application of it as against his arguments.