The subject of this chapter is a very difficult one to deal with in a manner at all satisfactory, and the writer is conscious that the want of minute knowledge, both theoretical and experimental, must render the task before him formidable in every way. Yet there is no intention of evading it, for the remarks which will be offered for consideration are based on a lengthened observation of the behaviour of billiard balls under various conditions, and will, it is believed, prove of interest, if not of use, some to one person, others to another, even though put forward in an unscientific manner.

In most books on billiards the subject is avoided; a chapter (of a page or two) is devoted to side, and those writers who have dealt with it most briefly have probably made the fewest mistakes. An exception, however, must be made in the case of M. Vignaux, in whose ‘Manual’ endeavour is made, with considerable success, to explain many phenomena in a homely way; and as the observations and deductions therein recorded often agree with those arrived at in this book independently, it is not remarkable that the courage which the Professor has shown in attempting a difficult subject should be admired, and that the skill which has led him to no small measure of success should be praised. Besides, in trying to convey instruction the teacher is much assisted, and the learner finds his task more easy, in proportion as the reasons for orders are understood. A rule whereby a player is desired to use right-hand side for a certain stroke from baulk to the top of the table, and left-hand side for a similar stroke from the top to baulk may be perfectly correct; but it is much more likely to be remembered and put in practice at the moment of need if the reason why has been explained and is known. Hence, some space will be devoted to the consideration of rotation, and it may be that when attention is drawn to the various effects, or some of them, due to this cause, a better qualified writer may be induced to study and deal with the subject in a more scientific and satisfactory manner. If this should happen, the remarks now made, however imperfect and conjectural, will not have been thrown away.

It has already been brought to the reader’s notice that a ball, when set in motion by the stroke of a cue, does not merely slide forward, but at once commences to rotate round its horizontal axis, which is at right angles to the axis of the cue, or the path of the ball. That is, in addition to the movement of displacement, or movement from one place to another (which can be effected by taking the ball in one’s fingers and placing it down in its second position), called by the French ‘translation,’ there is generated a distinct movement of rotation, which is for the most part latent and invisible till after impact with another ball or with a cushion.

That the motions are distinct is evident; for a ball or a cube may be so pushed or removed from one spot on the surface of the table to another that no rotation results. Again, the same ball may be made to spin or rotate by the action of the fingers, and dropped vertically on the table, so that no impulse forwards or backwards is communicated, and yet no sooner does the ball fall on the cloth than it will commence to travel in a line at right angles to the axis of its rotation. Hence, both motions may produce displacement or translation, and when both are at the same time active in a ball the path travelled, whether straight or curved, is the resultant of the two movements.

Now at p. 132–3 the divisions of balls were explained, and the same figure will suffice to assist in defining the various classes of rotation used in the game of billiards to effect different purposes at the discretion of the player. There are four main divisions, corresponding to the four sectors into which the lines H B and G D divide the ball.

(1) Forward rotation, or follow, is communicated by striking the ball on the line C H above the centre C.

(2) Backward rotation, retrograde, or screw, is obtained by striking the ball on C B below the centre.

(3) Right side,^[15] or rotation round the vertical axis H B from left to right, is attained by striking on the line C D; whilst

(4) Left side,^[15] or rotation from right to left, results from striking on C G.

And these can manifestly be combined; thus, the ball struck in the sector C H D has both follow and right side; struck in C D B the combination is screw and right side; in C G B screw and left side; and in C G H follow and left side. These are the practical divisions for purposes of play, but it must be borne in mind that so long as the cue is delivered horizontally the path travelled is the prolongation of its axis, of a line parallel to that axis, and the effect of the rotation communicated does not show itself, save to a very minute extent, till after impact with a ball or cushion. Then it becomes immediately apparent and often bewildering in the strangeness of its results. Who, for example, has forgotten the feeling of awe with which he first contemplated the result of a well-executed screw, ball 1 striking ball 2 smartly and thence returning to the point of the cue? And to this day the most consummate masters cannot explain some of the strange results whose practical effects are sufficiently well known.

Before passing from this figure it may be as well to explain that the maximum of rotation can best be effected, or most side given, by striking at the ends of the diameters H B and G D, on the principle of the lever being longest at those ends; but practically the limit is reached at the point on either line beyond which a miss-cue would result. Each player will in time find out this point for himself, and it is remarkable how practice improves the power. With it a man can hit clean and sharp further out on the arm of the lever—that is, further away from the centre—than is possible for an untrained person, and it will be found, moreover, that in time and by practice a delicacy of touch and increase of effect are acquired.

But what is this rotation, what causes it, and how is it regulated?

The main factor, or at any rate the main reason whereby its effects become visible and are regulated, is friction with the cloth or bed of the table. If balls were perfectly smooth, the bed also being equally hard and smooth, and if they were unaffected by the resistance of the air and the force of gravity, once set in motion they would continue to slide along for ever within the limit of the length of the bed. They would not roll, but would slide as a curling stone does on smooth ice. But the practical condition of affairs is different. In the first place, the surfaces of the balls, be they never so finely finished, instead of being smooth, are if examined under a microscope found to be palpably rough. The cloth, too, no matter how well stretched or of how fine a texture, is both soft and rough. A ball at rest on it is standing in a little cup, whilst one travelling forms a narrow groove, along which, it is plain, resistance will vary according to its direction and that of the nap of the cloth. If with the nap the friction will be less, if against it more.

Hence it follows that in considering the motion and rotation of billiard balls on a table, we must picture to ourselves a toothed-wheel working on a toothed-plane, and one toothed-wheel working into another, rather than a perfectly smooth surface on a similarly perfectly smooth plane, or two perfectly smooth spherical surfaces in contact.

The accompanying drawings, in which the roughness is purposely exaggerated, will convey the idea better than much elaborate description. No. 1 shows a ball in contact with the cloth, and No. 2 one ball in contact with another. From these it is easy to realise that a ball rotating has a bite of the cloth, and will travel along it in the direction of the rotation, and also that a ball rotating round its vertical axis brought into contact with another must transmit a portion of its rotation, the effect of which is to make the second ball revolve in the opposite direction, precisely after the manner of one toothed-wheel working into another. Such transmitted side is no doubt very small and difficult to perceive, save in the matter of results which cannot otherwise be accounted for. It is indeed probable that side can in this way be communicated to a third ball provided it be touching the second ball. By its means certain kiss strokes can be made which without the use of side are impossible. The subject is undoubtedly complicated, and the suggestions here offered may be wrong; they are those which, after much consideration, have commended themselves as most in agreement with known facts concerning the rotation of bodies, and as accounting for the behaviour of billiard balls in a manner which is not repugnant to common-sense. Nevertheless it must be admitted that absolute proof of transmitted side can scarcely be said to exist, that many experienced persons deny its existence, and, moreover, it is never safe to jump to conclusions.

Let us now consider the four classes of rotation which have already been defined, and begin with forward rotation or follow. This is the most important of all; for, as will be seen, it is present and active in almost every stroke unless special means are employed to counteract it. It is generated in two ways—spontaneously, and by striking the ball above its centre.

When a ball is struck by a cue in the centre, no rotation is thereby communicated. Its first impulse is to slide along with a velocity and for a distance proportionate to the force employed. But the instant that motion is communicated, resistance to sliding forward is experienced. The ball then is subjected to two forces, one from the cue impelling it forward, and the other a retarding force caused by the friction of the cloth. The impelling force drives C in the direction M, and the friction or retarding force acts on B in the direction B N. The point B is thereby retarded, and the result of the two forces is that C travels towards M, whilst A advancing, B being retarded, a rotatory motion is produced whereby A at the top gradually lowers its position till it reaches the bottom and rests on the cloth. It is evident that this spontaneous rotation exists in every plain stroke; it is separate from the mere displacing or translating force, and has a separate life. One may outlive the other; an ordinary example of this is when ball 1 is played full on ball 2. When the distance between them is small, little or no rotation has been acquired and the force of ball 1 is transmitted to ball 2, the former remaining nearly stationary, or dead, after impact; but when there is considerable distance between 1 and 2, rotation is well established and asserts itself after impact, which destroys the life of the force of displacement or translation. Thus ball 1 on impact stops merely for a moment, for rotation coming into play carries it forward on its original path. A very common illustration of this is unpleasantly familiar to young pool players. They cannot prevent their own ball from following into a pocket after a long straight hazard.

But follow can be increased or accelerated artificially, and the object of doing so is to augment the progress of ball 1 after impact. No gain in propulsion results from hitting a ball over the centre, for what rotation gains translation loses, and when there is no obstacle to run or follow through it is a mistake to strike above the centre, for a ball will travel less truly when so struck, and further, should it encounter unperceived obstacles, such as grit, or dust, or tobacco, the tendency to leap is enhanced by follow, and the result is greater or less deviation from the true path.

The chief use, then, of follow is to control deviation and prevent stagnation after impact. When a fine stroke becomes dangerous a follow may not only be safe, but may be played so as to leave a good game. The stroke should be delivered gently, smoothly, and the cue should be held as horizontal as possible, the butt being lowered, and the bridge raised so as to bring the tip opposite the part of ball 1 to be struck. After impact the point of the cue should be permitted to follow on with a flowing motion. Another and at first sight quite different use of follow is to decrease the velocity of rebound from a cushion or from a ball touching a cushion. The reason is that after impact rotation is reversed, and a stroke which reaches a cushion with follow rebounds with retrograde or drag. If played with strong follow, the ball will not improbably leap in the air after impact, and either stop short on reaching the bed or even return towards the cushion. As is perhaps evident from what has been explained, follow is very useful when balls 1 and 2 are so close that little or no rotation can be spontaneously acquired; its absence is supplied by striking ball 1 above the centre.

The next rotation to be considered is round the same axis—horizontal—as follow, but is in the opposite or backward direction, whereby what we call ‘screw’ and ‘drag,’ the French ‘retrograde,’ and the Americans ‘draw,’ are effected. The point of aim is on the line C B (p. 191, fig. 1), and the lower the ball is struck the greater the rotation, the limit being as usual where a miss-cue would ensue. To ensure striking low, the cue should be made to bear somewhat heavily on the bridge between the thumb and forefinger, and the butt should be slightly raised. The result of the stroke is that ball 1 is forced forward but does not acquire spontaneous rotation, that being counteracted by the inverse rotation or screw communicated by the cue. If the stroke be played the length of the table close observation will disclose a different behaviour of the ball from that which results from a plain stroke. In the first place, the ball will start for an equal transit or length of path with greater initial velocity, it will slow down much more abruptly, will apparently stop for a moment, and then continue its course till it comes finally to rest. Analysing this path, the first portion is traversed by the ball with inverse rotation and under the influence of a stronger stroke than would have been necessary had it been struck in the centre; the slowing down is the struggle between the screw or backward rotation artificially given and the spontaneous or forward rotation naturally acquired; the momentary check or stop is when the one rotation exactly counterbalances the other, and the ball on an instant slides forward without any rotation; and the final part of the course is when (the backward rotation being dead) the spontaneous rotation has conquered, and in turn dies with the force of displacement or translation. That is what is seen when a master of the art plays with drag. He uses it to overcome irregularities in the ball or bed, and is by its means enabled to combine the advantages of a strong and of a gentle stroke. If ball 1 cannot be trusted the length of the table for a slow hazard or cannon, the player strikes it comparatively hard with drag; the ball then runs fast over the greater length of its course, but pulls up in the manner and for the reasons above described, and reaching ball 2 with gentleness does not displace it to any great extent.

That is the complete stroke; but if it should happen that ball 2 is so near ball 1 that impact takes place before the backward rotation is dead, if the stroke be full the whole of the forward motion (translation) is communicated to ball 2, and ball 1, which has apparently stopped for a moment on the spot which ball 2 occupied, will return towards the point of the cue by reason of its inverse rotation or screw. The result is what is known as a ‘screw back stroke.’ The more full ball 1 is played on ball 2, the further will that ball travel and the greater will be the recoil and screw back. The finer ball 2 be taken, the less velocity will be imparted to it and the less will be the return of ball 1. Screw back is not possible, unless, perhaps, the balls are very near each other, if ball 2 be struck half-ball or finer.

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.

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.

The consideration of regulated screw leads to the insertion of fig. 5, in which a class of strokes of common enough occurrence, but little relished by players whether amateur or professional, is illustrated. They are intermediate between the path of a forcing stroke and that of the right-angle screw. Now the latter, though decidedly difficult when the balls are far apart, say 2 ft. or so, yet admits of some certainty in playing, for it represents about the maximum of most men’s power; but the intermediate strokes, though they require less execution, are yet oftener missed, because the player has no definite measure of them, no guide or clue to which he can trust.

If the paths represented from ball 1 to ball 2 and then to ball 3 be those of a hard forcing stroke, and the paths 1 to 2 and 2 to 3A those of a right-angle screw, the strokes referred to lie between the two, and may be represented by the dotted lines from 2 to 3B, 3C, &c. The balls may be set up as shown; ball 1 on the right spot of the Ｄ; ball 2 at the same distance from the side cushion line and opposite the centre of the middle pocket; ball 3 anywhere between the pocket and the limit of a forcing stroke in the positions marked 3B, 3C, &c.; or ball 1 may be advanced nearer to ball 2, in which case the strokes are easier. In either case practice at these intermediate angles will not have been thrown away if the remarks and advice respecting screw be appreciated and followed. Do not forget that when played with strength ball 1 will pass beyond ball 2 before the screw takes effect.

In practising the straight screw back it is advantageous to keep the cue exactly in position after the stroke, which, if true, will result in bringing ball 1 back to the tip. Also the behaviour of ball 2 after each stroke should be noted, in order that when playing in a game its position may be approximately foreseen. Always chalk the cue before attempting a screw.

Rotation round a horizontal axis having been considered, it is necessary now to examine side, or rotation round a vertical axis. This is communicated by every stroke of the cue which is not delivered precisely on the vertical line H B (fig. 6), and is, as may readily be conceived, generally applied unintentionally. In fact, much of the preliminary practice has been recommended in order that the power of striking a ball without side might be acquired. Still, when intelligently used, side gives great additional scope to a player and will well repay attention and study. To discuss right side and left side separately is unnecessary, for the one is simply and solely the reverse of the other.

Side, or rotation round the vertical axis, does not convey to a ball a movement of displacement or translation; on the contrary, its tendency is to bring the ball to rest, precisely as a top when thrown with heavy spin at first gyrates or travels a little, but soon comes to rest, or sleeps, whilst revolving at a great rate. Hence it follows that some compensating strength has to be used when playing with side.

Now, the student cannot have got so far, supposing that the various strokes have been practised, without having acquired some knowledge of the effect of side. He has learnt, for example, that the more out of the centre his ball was struck, the more did the angle of reflexion vary from the angle of incidence; if struck on one side, the angle of reflexion was enlarged; if struck on the other side, it was diminished. Side also makes some, though less evident, modification in the angle of deviation after impact with another ball. The proper mode of communicating side to a ball by means of a cue must now be considered, G H D B is a ball standing on the table T T; H B is its vertical axis, C its centre, E and F represent the cue-tips at the moment of striking the ball: E for right side, or side which tends to take the ball towards the right, and F for left side, which will carry the ball to the left. It will be observed that the cue is delivered on the central horizontal line, for on it the maximum of rotation round the axis H B can be given; in other words, the height of the stroke is precisely the same as that for a plain or true centre stroke, and is equal to half the height of the ball.

The next point is the proper alignment of the cue. In a plain stroke it has been shown that the path of ball 1 previous to impact is the prolongation of the line of the cue’s axis. For a side stroke, the point of aim being the same, the only difference is that ball 1 must be struck on the side instead of in the centre. Hence, to preserve the same path, the cue’s axis must be parallel to that in the plain stroke and distant from it in proportion to the amount of side to be given.

Fig. 7 illustrates the chief points connected with side strokes, and admits of comparison between them and an ordinary plain stroke. Ball 1 played half-ball plain on ball 2 travels the path shown by the continuous line 1 1′ 1″ and 1‴, and the angle at which it comes off the cushion is nearly equal to that of approach. The position of the cue is the central one on the prolongation of the path 1 1′. The same stroke played with right side is thus effected: the cue is moved to the right, its new axis being parallel to the original axis. The stroke is delivered in precisely the same way and in the same direction, save that the point of ball 1 struck by the cue is to the right of the centre. Ball 1, if struck with the strength of a full No. 1 or more, travels practically the same path until it strikes ball 2, after which it deviates slightly to the right, following the path marked by dot and dash alternately, and reaches the cushion at R, whence it flies off at an enlarged angle in the direction of R′. Right side for the stroke figured increases the velocity of ball 1 after impact with the cushion, from which it shoots perceptibly faster than does a ball plainly played. Hence, this side is termed direct, being given in the direction that the ball is intended to travel.

Played with left side, the cue is shifted to the left of the centre, but is still parallel to the original direction. As before, on delivery of the stroke ball 1 travels to ball 2, but after impact follows the dotted line 1′ L L′, returning from the cushion at once more perpendicularly and with reduced speed, the left side with which ball 1 is charged tending to reduce velocity, specially after impact with the cushion. In respect to this stroke, left side, conveying as it does rotation in a direction contrary to that of the ball’s path, is termed reverse. Of course, if the other side of ball 2 were played on, the left side would become direct and the right side reverse.

There, in a nutshell, lies nearly all that is essential in the matter of side. A man with ordinary powers of thought can for himself apply the lesson either to cannons or to losing hazards, and nothing but practice, as far as possible under the supervision of a master, will suffice to produce the confidence and certainty which is necessary to good play. Be careful about the alignment of the cue; see that the left hand, which forms the bridge, is so placed that the part of forefinger and thumb on which the cue lies is precisely opposite the point on ball 1 to be struck, and as there is special danger of a slip or miss-cue when much side is used, never neglect to chalk the cue carefully before the stroke. Attention to this, though it seems but a small and self-evident matter, will save many a game and much temper.

There are, however, certain other matters connected with rotation which, though not so important as what has already been explained as far as the game of billiards is concerned, are yet of considerable interest, partly as they affect the game, but chiefly in so far as they may add to our knowledge of the various forces which affect a ball in motion. Amongst these is the side which may be acquired from friction with the cushion. The probability that such side is so acquired is understood, but the conditions are little known. M. Vignaux remarks that it depends on the angle of impact, on the velocity, and on the strength; and he gives as an example a plain stroke played gently in a corner of the table, when the ball always has a tendency to come off at a diminished angle of reflexion, specially when the angle of incidence is about 45. The side acquired is probably greatest when a ball is played along and touching a cushion; if played from baulk up the left cushion the tendency would be for the ball to acquire right side, and up the right cushion left side; but all such strokes are complicated by the much more important friction with the cloth on the bed of the table. It is unnecessary here to speculate further on a matter which so slightly influences the game. Of vastly greater significance, though its action is still most imperfectly apprehended, is the effect of the nap of the cloth on the rotation and path of a ball. Amateur players scarcely understand the subject at all, and no doubt the habitual strength with which they play in a great measure destroys or smothers the effect of the nap, which tells more when the execution is delicate. There is also another reason why they are ignorant of its effect, which is that markers, to please the great majority of their patrons, smooth and iron away the nap in order to make the table faster. By this means they ruin it for the very few who can play, for without plenty of nap the slow screws and gentle side strokes will not tell, the ball, so to speak, cannot obtain a bite or grip on the cloth, and the result is that strokes which should be played softly, and from which the position of the balls can be foreseen with some accuracy, have to be forced, and an ignorant hard hitter may on such a cloth defeat a player of a much higher class. Thus the common fault of amateurs, in attempting by strength results which should be effected by skill, prevents them from acquiring a practical knowledge of the use of nap, which is consequently sacrificed, to the detriment of the game. It is scarcely an exaggeration to say that there are but few tables in London clubs the cloths of which are in fit condition for play.

Now, though the professional scarcely understands better than the amateur why the game can be more scientifically played on a cloth with nap, yet from practice, and because of his habitually gentler touch, he prefers a slower table and a cloth with proper nap. For all serious matches a new cloth is used; and in some cases when the game is very long, extending for two weeks, a condition is made that one player shall supply the cloth for one week and the other for the next. Of course there is a limit to the amount of nap which is desirable; it is quite possible to have a cloth which is too coarse and rough, but the usual mistake is the other way. Persons are apt to think that the more friction is reduced the better; but it is not so, and even an average club amateur would find if he tried to play on glass or ice how impossible many ordinary strokes would become.

In a general way, in very delicate strokes side should be reversed when playing against the nap. Many examples can be shown, and a good professional will easily set them up on the table. One may be mentioned here, as it affords an excellent illustration of the general principle. If ball 1 be in baulk, almost touching the left cushion, and it be desired to run a coup in the left top pocket, a gentle stroke with side next the cushion, or left side, will cause the ball to hug the cushion and fall into the pocket. But reverse the stroke, play from the top of the table down the same cushion; if cushion side, or right side, be used, the ball will run fairly straight as long as the forward force (translation) overcomes or neutralises the side; but whenever the latter can assert its power the ball will show a distinct tendency to leave the cushion altogether. It will even strike the bottom cushion 6 in. away from the side cushion, and return towards the latter by reason of the side. Play the same stroke with left side—i.e. side away from the cushion—and as soon as the side tells the ball will most distinctly hug the cushion, and if repelled from it will endeavour to return again. At present the full effect of playing with or against the nap is neither understood nor practised, but it has attracted attention, and the more skilful and thoughtful players are studying and utilising its effects. It is sufficient here to notice a refinement of play from which considerable development may confidently be expected.

Many diagrams are unnecessary for this chapter, which is rather an essay or series of suggestions on matters connected with rotation than part of a manual of billiards; examples of following, side, and screw strokes will be dealt with in the next and subsequent chapters. Still, practice is useful at this stage, and some strokes are accordingly indicated. The opening stroke of a game may be taken as the first example. Place ball 1 in baulk on or close to the baulk-line A B and at a convenient distance to reach, say, the centre spot, or, perhaps better still, an inch or so beyond it, in order to avoid playing from a spot which, however thin, must on a new cloth, at any rate, be raised above the general level. If the player stands at A, he should strike ball 1 with right side and strength sufficient to take it to the cushion above B and back as nearly as possible to the central longitudinal line of the table, or below the centre baulk-spot, thereby securing a good position, marked P, and making his opponent’s next stroke, also usually a miss, as difficult as possible. If played from B, left side must be used, and the stroke must be practised till complete confidence as to angle and strength is acquired. Then marks should be set up at C, D, E, F, and each stroke practised till ball 1 can be brought with fair accuracy to follow the lines B C, B D, B E, and B F, which, as is seen from the figure, will result in a coup in the left bottom pocket. At first this is about the maximum of side a beginner can command, but after some practice he will succeed in striking the bottom cushion near G, a stroke which is useful when a ball is left over the pocket, as a losing hazard may be made with sufficient strength to bring ball 2 out of baulk. These strokes should be played from B as well till some certainty is acquired. They are very useful for disturbing a double baulk, and even for scoring from one, and a good break so made has a somewhat disconcerting effect on the adversary.

A side stroke played back to baulk is shown in Diagram I. Place ball 1 on the right corner of the Ｄ, and play on the left top cushion 14 in. above the middle pocket with a little right side a free No. 2 strength; the ball should follow approximately the course indicated, and run into the left bottom pocket. Similarly played from the other corner of the Ｄ to the right top cushion, the ball should fall into the right bottom pocket. These strokes are often useful in a game when a double baulk is given and one or both balls are over a pocket. A little modification too, either by aiming higher or lower on the top side cushion, or by using more side, makes this stroke available for cannons in the neighbourhood of the bottom pockets, and for disturbing the balls when the adversary has left a certain score for himself in the corner.

The next stroke is also well worth acquiring. It is differently played by different people, but the main point is to bring the ball on to the bottom side cushion a few inches below the middle pocket. If that is done the path thence is practically a straight line to the centre of the bottom cushion. It is interesting to practise thus: place balls 2 and 3 as shown in Diagram II. on the central longitudinal line of the table, ball 3 near the bottom cushion, and ball 2 immediately above, but not necessarily touching it. Set ball 1 on the baulk-line about the centre spot, play at the side top cushion, 30 in. from the pocket, a free No. 2 with a little direct side. The stroke can be played off either right or left side top cushion, and should be tried from both. It can also be made from the corner spot of the Ｄ, aiming at a point 15 in. above the pocket, if the stroke be played more gently and the side correctly regulated. It follows, therefore, where there is so great possible divergence in the manner of play, that each person should find out that mode which best suits him, and practise till confidence is gained. The cannon may be made in many ways, sometimes as indicated, on other occasions ball 1 will strike the bottom cushion first and thence cannon from 3 to 2, and so on, showing that there is considerable latitude for error in striking. Once the player realises the path of ball 1 from below the middle pocket to the centre of the bottom cushion, it is clear that many possibilities of scoring cannons in baulk are opened. The reader can no doubt supply them for himself, and it is well that he should take the necessary thought to do so; but one example is indicated. If balls 2 and 3 occupy the positions 2′ and 3′ the same stroke will probably result in a cannon. Mr. John Roberts often uses this stroke or a modification of it, and when the result is successful the delight of the spectators is unbounded; they applaud and regard him with the awe and respect due to supernatural power. Yet there is nothing remarkable in the stroke. Mr. Roberts knows approximately the course of the ball after it has struck the bottom side cushion, he sees that ball 2 is on or near that path, and therefore that there is a fair certainty of his hitting it, and if he does so on the proper side the cannon on 3′ or 3″ is probable. It is well to be conversant with strokes of this nature, though as a rule they should only be resorted to when clearly necessary, and never used simply to show off or to bring down the gallery.

Other examples might obviously be added, but these are sufficient to illustrate the principle, which is, when learning the stroke, always play it as nearly as possible in the same way and under the same circumstances. The result is that the eye becomes familiar with the tracks of the ball, and then moderate ingenuity and observation will serve to guide the player when he may make use of his knowledge to advantage in a game.

This chapter, wherein are raised interesting and suggestive questions which may hereafter be more thoroughly investigated and applied to the game, may be appropriately closed by an illustration, the idea of which is borrowed from ‘Modern Billiards,’ the text-book of the American game, prepared by the Brunswick-Balke-Collender Co. of New York.

Place fig. 9 so that A is in position for reading, and follow is illustrated. Reverse it, bringing B into position, and screw or drag is shown. Bring C into position for reading, and a side stroke, in this case right side, is represented; and if this be reversed, D being brought into position; the massé stroke, which will hereafter be explained, is seen.