The phenomenon of the uneven flight of the smooth golf ball has never, so far as I am aware, been satisfactorily explained. We all know, of course, that practically nothing which has not a tail flies well. A tail is necessary for an arrow, for an aeroplane, for a bird to steer itself with, and even the rifle bullet would not fly well until it was, in effect, provided with a tail. It has always seemed to me that there was a possibility of an explanation of the defective flight of the smooth golf ball in this fact. It stands to reason that in the passage of the ball through the atmosphere there is a considerable compression of the air in front of the ball, and it is equally obvious that this compressed air is, if we may so express it, flowing backwards over the ball, and therefore running between the bramble markings. Of course, we are aware that it is not really a question of the air flowing backwards, but of the ball driving through the atmosphere, but we have merely to consider what may possibly be the effect of this action.

It seems to me that the air, in passing back and round the ball in the manner described, is also in a state of compression until it has passed backwards and, to a slight extent, behind the golf ball, so that we have, if we may so express it, attached to the ball a tail of compressed air which is constantly striving to resume its normal density at a slightly varying distance behind the ball in its passage through the air.

If my idea, which is expressed now in an extremely unscientific and popular form, is correct, it would seem that the roughened ball holds more straightly into this tail of compressed air than it would be possible for a smooth ball to do; in other words, it seems to me that there would be a greater possibility of the smooth ball slipping the pressure which would be accentuated on that portion of the ball which Professor Thomson describes as its nose, and it seems feasible, although I do not care to be dogmatic on this point, that if the centre of gravity of the smooth ball were untrue, as indeed the centre of gravity of nearly every smooth ball is, the effect of the pressure of the condensed air on the front of the ball would be much more pronounced with the smooth ball than it would in the case of the ball marked by excrescences or indentations.

I am aware that this idea of mine is open to argument, and I do not say for one moment that it is absolutely correct. It is undoubted that there is much uncertainty in the minds of extremely scientific men as to the cause for the uncertain flight of the smooth golf ball. Even so distinguished a scientific inquirer as Professor Sir J. J. Thomson assured me that he did not understand the reason for the erratic behaviour of the smooth ball. There is possibly another explanation, but again I put this forward tentatively. Even when a ball is driven by a golf club without appreciable spin, as indeed most golf balls are, it seems to me quite possible, especially in the case of the balls with defective centres, that before they have gone far on their journey they will proceed to acquire spin on account of the tendency of one side to lag more than the other.

It seems, then, that if this spin is set up in the manner which I described, it may, and indeed quite likely will, influence the path of the ball sufficiently to deflect it from the original line of flight, but as this spin has no very great power behind it, it seems quite likely that when it has deflected the ball from the line of flight it may be checked to such an extent that the atmosphere has a chance to get to work on the ball again and produce that which is practically a reverse spin. In this way, and in this way alone, can I see any reason for the double swerve which I have already referred to, in the carry of the golf ball. It must be understood that in the case of double swerve which I am referring to, the deflection from the straight line has always occurred at a point in the carry where one would not expect to see it if it had been occasioned by spin administered by the club, and it is always very much less indeed than the swerve would be if it had been obtained by spin produced by the club.

Also there is this other fact against the hypothesis that the swerve is produced by spin imparted at the moment of impact. In the swerve which I am referring to, both the first swerve and the return swerve which takes the ball back again into the line of flight are very slight, and in most cases practically of the same length and degree. If the original deflection from the straight line were due to rotation of the ball acquired at the moment of impact, the swerve and return to the straight line, if there were any such return, would never be so symmetrical as they are.

I can quite easily understand the double swerve of a golf ball from spin produced by the contact between the club and the ball, although I must admit that I have never seen a swerve of this nature in golf which I could put down unhesitatingly to spin acquired at the moment of impact. I must, however, when I say this, except one instance. This was in the case of a ball hit with back-spin, and although it is in a sense improper to refer to it as double swerve because it only affected the trajectory and did not alter the plane of the ball's flight in any way, it was, in a sense, a case of double swerve. It was a wind-cheater struck by a very good player at Hanger Hill. The ball flew very low and looked as though it was about to hit a bunker, when suddenly, on account of the tremendous amount of back-spin which the player had put on his ball, it rose with the ordinary rise of the wind-cheater and soared straight away for thirty or forty yards, when it began to tower in the ordinary manner of the windcheater. This was such an extraordinary shot that I illustrated it in Modem Golf, but I have never, in the course of fifteen years' acquaintance with the game, seen another shot of the same description.

There is no doubt whatever that double swerves may be obtained by the axis of rotation of the ball altering during the flight of the ball. I can remember quite clearly at a meeting of the All-England Lawn-tennis Club at Wimbledon, a player informing me quite seriously that a lawn-tennis ball would swerve two ways in the air. At that time I was under the impression that I knew all there was to be known about the flight of the ball. I did not contradict him, but inwardly I pitied him; but at the same time I made up my mind to watch for this phenomenon, little as I expected to see it, for in the course of at least seventeen years' practical acquaintance with the game of lawn-tennis wherein one has a splendid opportunity of observing the action of spin on the ball, I had never seen, or perhaps it would be more correct to say I had never observed, any ball swerve two ways.

It was not many days after this that I distinctly saw an American service, delivered by one of the players in the All-England Lawn-tennis Championship, swerve two ways. Since then I have looked for this phenomenon, and I have seen it happen both in lawn-tennis and golf, but I am satisfied that in golf it is not due to spin acquired at the moment of impact, as undoubtedly it is in lawn-tennis. It seems to me that with the lawn-tennis ball, which offers a very large frictional area in proportion to its weight, that it is quite feasible that during its travel, particularly in the American service, it may alter its axis of rotation on account of encountering a heavier bank of air, or for some other reason. It naturally follows that immediately this takes place the arc of the original swerve is interfered with, but in no case have I seen in lawn-tennis, as I have in golf, the original swerve of the ball exactly compensated for by the swerve back into the straight line, which is the peculiarity of the double swerve at golf.

There is no doubt that there is a considerable amount of mystery in this matter. It may appear that it is not of much importance to golfers, from a practical point of view, whether it is solved or not, but it is hard indeed to say how useful a proper understanding of the higher science of the game may be in the practice of it; and in the experiments carried out by Sir Ralph Payne-Gallwey with so much patience and ability we have a very good example of the value to golfers of the scientific investigation and consideration of matters appertaining to the various implements of the game.