When the student has acquired confidence that he can play ball 1 on ball 2 direct and full and screw back, he may with advantage study the various angles at which ball 1 will come off ball 2 when hit at certain divisions between full and half-ball. A convenient mode of practising these strokes is to place ball 2 on the baulk-line, and ball 1 6 in. to 8 in. below it.
Thus, if ball 1, struck three-quarters low, or wherever the player can communicate most screw, be played full on ball 2, the latter will travel up the table parallel to the cushion, whilst ball 1 will return over the position it occupied, also parallel to the cushion, in the direction of the bottom cushion. The distance travelled will depend on the strength and truth of the stroke as well as on striking ball 1 so as to obtain the maximum reverse rotation. That is the limit in one direction of the screw stroke; the other limit is to aim at the edge of ball 2, ball 1 being, as before, struck three-quarters low. In this instance the path of the latter after impact is along the baulk-line, or, in other words, practically perpendicular to its path before impact. That is what is known as a ‘right-angled screw,’ a most useful stroke to master, as is evident after a moment’s consideration. In the first place, if ball 3 were situated anywhere along the baulk-line, a cannon becomes a reasonable probability; and next, if there were a pocket at either end of the baulk-line, the losing hazard would be far from impossible. The way to acquire confidence in this right-angled screw is to begin softly, but always endeavouring to give ball 1 the maximum of screw. The beauty of the stroke is that it is impossible to give ball 1 too much screw, and that its path, when struck truly, must lie on the baulk-line; if it leaves the baulk-line and goes up the table, then ball 2 has been struck finer than half-ball, or ball 1 has had insufficient screw given, or both; if it comes back from the baulk-line, ball 2 has been struck fuller than half-ball. So here, again, is an example of a practice stroke which records exactly the causes of failure, thereby saving much time in fruitless inquiry, and pointing directly to the required remedy.
Now, having acquired the power of bringing ball 1 back from ball 2 in a direction perpendicular to the baulk-line, and also of screwing off ball 2 along the baulk-line, it follows that by subdividing ball 2 between full and half-full, and by regulating the strength used, the path of ball 1 after impact can be foreseen, and it may be made to travel thereon with some certainty. Thus 1 played full on 2 returns towards A; 1 half-ball on 2 travels towards L or B; when struck fuller than half-ball it returns towards C or K; fuller still towards D and H; and so on in succession towards E, F, and G. Now the acquisition of these strokes is not nearly so difficult as it seems, specially when a cannon is played for, and the power and confidence acquired by knowing that wherever a ball is situated—for example, anywhere on or near the various lines drawn on fig. 4—there is a reasonable prospect of scoring, are of great advantage.
Fig. 4
In the example just explained ball 1 is supposed to be near ball 2, say from 4 in. to 8 in. distant; when they are further apart the stroke must be played with greater strength, and ball 2 must be struck fuller to compensate for the tendency of ball 1 to travel past the position which was occupied by ball 2 before the screw takes effect. As the distance between the balls increases so must the strength of the stroke be greater, and so also must ball 2 be struck more nearly full.
This question of regulating the strength of screw strokes is of great importance. The general rule is as above stated, but there are many instances when a player, to obtain position, will vary the stroke. Thus, in order to make ball 2 travel he will play fuller on it, reducing the amount of screw, though the stroke might be equally certain if played gently, half-ball, but with more screw. There must be no slavish adherence to any one division of ball 2; the screw must be made at will off a full, fine, or intermediate ball, and the strength must be varied to suit the division of the ball, and the distance between the two balls.
At the risk of incurring the charge of repetition, let it be further explained (for this elementary fact should never be forgotten) that the reason why greater strength and more screw must be used as the distance between the balls is increased is because of the tendency ball 1 has to develop rotation in the direction of its path. When the balls are near each other but little spontaneous rotation can be acquired, and therefore ball 1 need not be struck hard or very low; when they are very near, the spontaneous rotation is so slight that in order to screw it is unnecessary to strike ball 1 below the centre. On the other hand, when the distance between the balls is increased, the opportunity for acquiring forward rotation or follow is greater; and greater, therefore, must be the strength and screw used for its conquest. That being so, it is further necessary to abandon attempts to screw off the finer divisions of ball 2. Endeavours to do so will end in failure, for the needful strength will carry ball 1 past ball 2 and the screw will be overcome. Hence the necessity for playing more and more full on ball 2 as the strength of stroke is increased. The fuller the stroke the more is forward motion transmitted to ball 2, and the less is the screw imparted to ball 1 interfered with. These matters, which are very difficult to deal with in a lucid way on paper, can be plainly demonstrated on the table without much trouble; there the student should repair with his instructor, and soon what may seem confused and useless in the above remarks will appear plain and of great value.
Fig. 5