Braid quotes an experiment which was made by Professor Tait in the course of his investigations with regard to the qualities of under-spin. It appears that the Professor laid a ball to the string of a crossbow, the string being just below the middle of the ball, so that when it was let go it would impart a certain amount of under-spin to it. When he shot the ball in this way he made it fly straight to a mark that was thirty yards distant; but when he shot it a second time, pulling the string to the same extent and laying it to the middle of the ball so that no under-spin would be given to it, the ball fell eight feet short of the same mark.

It is impossible to accept such a rough and crude experiment as this as evidence in any way whatever of the influence of back-spin in the drive; rather it would seem to show beyond a shadow of doubt that the extra carry was obtained because the power of propulsion was applied to the ball at a lower portion, and therefore tended to give it a greater trajectory. It should be obvious that this result would be obtained even disregarding the question of back-spin, which in such an extremely short flight as thirty yards would certainly not have any opportunity whatever to make such a difference in the length of carry as that suggested.

It is, however, when we come to deal with questions of practical golf that we find that the ideas of the late Professor Tait will not bear looking into.

Braid says:

However, it is well to bear in mind one thing that the Professor said, "The pace which the player can give the club head at the moment of impact depends to a very considerable extent on the relative motion of his two hands (to which is due the 'nip') during the immediately preceding two-hundredth of a second, while the amount of beneficial spin is seriously diminished by even a trifling upward concavity of the path of the head during the ten-thousandth of a second occupied by the blow."

Here we have plain evidence of the fact that Professor Tait is under the impression that there is some particular snap which he calls "nip" imported into the stroke immediately before impact. We have already dealt fully with this matter. We remember what Vardon has said in condemning the idea, and we know that Braid himself has confessed that he knows nothing about the matter, so it will not seem disrespectful if we come to the conclusion that we can disregard this vague statement about the "nip" in the blow. We can then proceed to notice the really important remark made that "the amount of beneficial spin is seriously diminished by even a trifling upward concavity of the path of the head during the ten-thousandth of a second occupied by the blow." It seems to me that this last statement is absolutely accurate, and it is the thing which I have always contended for in dealing with the practical side of golf driving, as contradistinguished from the purely theoretical, which has been put before us by Professor Tait, and following him, by Professor Sir J. J. Thomson. It will be observed that Professor Tait said that the amount of beneficial spin is "seriously diminished by even a trifling upward concavity of the path of the head during the ten-thousandth of a second occupied by the blow."

Some of my readers may remember that when I was dealing with Professor Sir J. J. Thomson's lecture before the Royal Society in an article which appeared in The English Review in February 1911, I stated that what actually did happen was that there took place in practically every drive at golf exactly this "trifling upward concavity of the path of the head during the ten-thousandth of a second occupied by the blow," and that therefore the amount of beneficial back-spin obtained from the loft of the club was practically negligible.

It is quite clear that Professor Tait was under the impression that back-spin was got from the loft of the club proceeding in a horizontal direction, but it is well known now to golfers who give the science of the game any attention whatever, that back-spin is not obtained in this manner, and that back-spin so obtained would be practically ineffectual as an aid to distance, for the loft of the driver and the brassy is not sufficient, even if the golf drive were played in the manner suggested, to produce any considerable amount of back-spin. As we have already seen, the beneficial back-spin in the golf drive is obtained by the club striking the ball long before the beginning of the "upward concavity of the path of the head," that is to say, in its arc as it is proceeding downwards to the lowest point in the swing from which it then starts that "upward concavity."

I have emphasised and re-emphasised this matter, for it is evident that when famous men like Professors Tait and Thomson start out with an absolutely erroneous idea, an idea which is fundamentally wrong, it is quite natural for less gifted men to be led astray. Braid says, and it must be remembered that this is in Advanced Golf (page 229): "So far as I know, it cannot be stated in accurate scientific terms and figures, and by lines drawn on paper, what is the proper scientific swing in order to get the best drive." This seems to me, especially in a book like this, to be a wonderful statement, particularly when we are dealing with the scientific results arrived at by men of the greatest eminence, results which I may say have been known for more than two hundred and fifty years.

There is no doubt whatever which is the best way to swing in order to get the best drive, and it can be explained in scientific language and shown by diagram and by figures, and in fact it has been so shown again and again. Braid says:

What golfers have done, therefore, in the past has been to find out gradually which is the best way in which to hit the ball in order to make it travel far, and thus they have groped their way to the stances and swings which, if the truth were known, would probably be set out by science as the best possible ones for the purpose.