under-spin does this, we have just seen, and readers will now have a very definite perception of the qualities of a ball and the importance of rotation, and though the chief advantage of rotation is in resisting gravity, it is an incidental advantage of it, as will now be understood, that the flight of the ball is thereby steadied, and a very slight inaccuracy in centering made of less consequence than it would otherwise be. But remember that a considerable inaccuracy in centering will interfere with the rotation, and therefore the bad flying ball can still be distinguished, because it will fly badly. VI Now, in continuation of this brief and simple exposition of some of the points of the Professor’s theorising--backed up by constant practical experiment--upon the merits of under-spin in prolonging and lengthening the flight of the ball which created excited comment in the world of golf at the time, much smaller as that world was then than it is now, it may be mentioned that it was his fair conclusion that good driving lay not in powerful hitting, but in the proper apportionment of good hitting with such a knack as would give the right amount of proper spin to the ball. Thus, while a player who gave no spin to his ball might attain a carry of 136 yards, another one who hit his ball with just the same force, giving it the same initial speed, but also a moderate amount of under-spin, would get a carry of 180 yards. Of course there would be a great difference between the trajectories of the two flights. By an experiment on a small scale he showed very conclusively what under-spin did. By shooting a ball from a very weak bow, but with the string just below the middle of the ball, so as to impart a slight spin, he made the ball fly point blank to a mark thirty yards off. When he drew the string to the same distance, but applied it to the middle of the ball, it fell eight feet short. It had no under-spin the second time.