Braid proceeds:

Of course, as already indicated, the golfer does not know, and in one sense does not care exactly how much under-spin he gives to his ball when he drives it, only being aware that he has given too much or too little according to results, and knowing also that in either case excess or otherwise was due to faulty stance or swing - most frequently this - or both. In the present case of this high trajectory, the exact amount of under-spin given to the ball is half as much again as that given to the properly driven ball, and under the same normal conditions these would be the relative flights of the two balls.

Now it is obvious that if Professor Tait was under the impression that the beneficial back-spin of golf was obtained merely from the horizontal blow delivered through the centre of the ball's mass, so that the ball took some slight spin by its roll up the face of the club, he had no very accurate idea of the rate of spin of that ball at the moment it left the face of the club, so that any attempt whatever on his part to measure the respective rates of spin of the different flight of these balls must be received with very great caution. As a matter of fact the rate of spin of the golf ball at the moment it leaves the club in a well-played drive with back-spin would be immeasurably faster than anything supposed by Professor Tait, who based his calculations on the ball obtaining this back-spin from the loft of the club, which is undoubtedly a grave error, and Braid wholly subscribes to this error, which is not to be wondered at, for Professor Sir J. J. Thomson, one of the most eminent scientists, has fallen into the same trap.

Professors Tait and Thomson and James Braid talk much about the possibility of obtaining too much back-spin in the drive. This is scarcely theoretically possible in golf, and it is practically impossible. I will give an example taken from practical golf which will, I believe, quite convince any golfer that the possibility of obtaining too much back-spin in the drive need never be considered.

Let us imagine a very badly sliced ball. By a badly sliced ball I do not necessarily mean an extremely quick slice where the ball leaves the line of flight to the hole quite suddenly, nor do I mean a ball pushed away to the right of the line to the hole; what I do mean is a ball which has been so sliced that it takes a tremendous curve from left to right, beginning to develop that slice in a pronounced manner at, say, half to two-thirds of its carry, which is quite bad enough for a slice. We frequently see in such a case, particularly on a windy day, and even on a still one, the great power which the spin has to deflect the ball from the line to the hole. It must be remembered that in this curve the spin is assisted by gravity - the ball is falling much of the time as it is being edged away - and even then it will be apparent that it is easy to get much greater spin in the slice than it is in the wind-cheater, for the simple reason that in the slice one has an unrestricted cut across the ball, whereas one has not this opportunity with the wind-cheater, for one hits the ground immediately one passes the ball.

Now although it is possible to apply an infinitely greater cut to the slice than one can possibly do to the wind-cheater, the deflection from the line, except on a very windy day, is, comparatively speaking, gradual. That is to say that if, for the sake of argument, the trajectory of the slice could be turned upwards there would be no possibility whatever of the ball showing such a thing as a curl backwards towards the hole, which is shown by Professor Tait and, following him, by Professor Thomson. This is clearly so in any slice which is not an extremely exaggerated specimen, so it stands to reason that in the wind-cheater, where one's opportunity for applying cut is so restricted, and where the ball in its effort to climb upwards has to fight the direct pull of gravity, there is no possible chance of applying too much back-spin to the ball.

At page 239 Braid says: "It may be of interest to mention that Professor Tait found that a well-driven ball turns once in every 2 1/2 feet at the beginning of its journey." If Professor Tait found that a golf ball, obtaining this back-spin in the way in which he thought it did, turns "once in every 2 1/2 feet at the beginning of its journey," he would probably have found, if he had realised how back-spin really is obtained, that the number of revolutions at the moment that the ball is leaving the club are at least three or four times as many as he asserted. It is unnecessary to enlarge upon the fact that this would mean a lifting capacity infinitely beyond anything that Professors Tait and Thomson ever ascribed to back-spin in the drive. Braid continues:

We have so far only been considering the effect of the spinning of the ball in the case of long shots with wooden clubs. As a matter of fact, and as suggested at the outset, it has also very great influence on the play in the case of the shorter shots with iron clubs, as may be understood after a very little consideration of the circumstances. It is the excessive under-spin that is given to the ball by the angle at which the face of the club is laid back, and the peculiar way in which the stroke is played, that make the ball rise so quickly and so high in the case of a short pitched approach, and then make it stop comparatively dead when it comes to the ground again.

It is obvious here that Braid is under the impression that the loft of the club is largely responsible for the back-spin in the approach shots, but this is quite an error, for not one player in a hundred does apply back-spin to his lofted approaches unless he has been specially taught how to do it, for, curiously enough, the more lofted the club is, the greater chance is there that the player will at the moment of impact impart into his stroke that little bit of "upward concavity" which Professor Tait says, and truly says, is the enemy of back-spin. The fact is that very little under-spin, or, as I always prefer to call it, back-spin, is obtained from the loft of the club unless the blow is delivered as the club is travelling downward. That is the whole essence of the secret of back-spin, but it is not mentioned by Professors Tait or Thomson, or by James Braid. Any attempt whatever to obtain back-spin from the loft of the club will be practically useless. It must be obtained by the method of playing the shot, and the only way to obtain it effectually is to hit the ball before the club has arrived at the lowest point in its swing. By this means, and this means alone, is it possible to obtain the beneficial back-spin of golf, and I cannot say too often or too emphatically that anyone who trusts to the loft of the club to produce back-spin will be disappointed.