To the Editor.
Your contributor Mr. A. L. Onslow, in his article on "The Peculiarities and Effects of Side on a Ball," states that running side causes the cue ball "to roll for an instant away from the object ball, whereas check side causes it to roll towards the object ball." Has he not inadvertently used the words running side for check side and check side for running side? Especially as in the next paragraph he refers to the buoyant manner in which the cue ball leaves the object ball when running side is used and the listless way in which it leaves it when check side is used. He also mentions that though Mannock in his book refers to this virtue of running side in gentle screws, he makes no attempt to explain the cause of it and considers him wise not to have done so.
After reading his article, many of your readers may have concluded that Mr. Onslow 5s the only writer who has attempted to explain the reason that the cue ball leaves the object ball so differently according as to whether the stroke is played with running side or check side. In proof that this is not so, I beg leave to quote the following extract from the chapter on" Screw and Reverse Rotation "in my work "Billiards: The Strokes of the Game "—
"Few ordinary players are aware of the assistance to be gained from running side, when playing slow screws, but this virtue of running side is regularly made use of by professionals and good amateurs when good after-position depends upon the stroke being played with very little strength The reason that the cue ball can be made to screw a certain distance with less strength when running side is used, than when check side is used, is because a ball spinning with running side is, at the moment of contact with the object ball, rotating in the direction it has to travel, and is consequently thrown off the object ball with extra pace, much in the same way as though it had touched a cushion; whereas, when it is spinning with check side, the rotation at the moment of contact is in the reverse direction to that in which the object ball is thrown."
And in the next paragraph there is the following sentence bearing on the same question:—
"Played with running side, the stroke is, however, much easier than if played with check side, for, as already explained, running side causes the cue ball to travel considerably faster after contact than it would were it spinning the reverse way with check side."
More scientific analysis of the question would have been outside the scope of my work, and I therefore contented myself with the above explanation, which can easily be understood by the ordinary non-scientific player.
Riso LEVI.
Manchester
September 20, 1913.