1831. 
An Esscnj on the Game of Billiards. 
399 
A ball, somewhat obliquely hitting another, close or near to the cushion, after 
being repelled to some small distance by the kiss, frequently returns to the cushion, 
or runs into an adjacent pocket. This (at first view) may seem extraordinary ; 
but, it is to be noticed, that, without increasing the progressive velocity of the 
ball, a force may be superadded, which will carry it farther ; and, that the 
progressive velocity which remains after hitting, may be completely destroyed, 
without necessarily annihilating the rotary motion also. For (see fig* 20) sup- 
pose A and P, vertical sections of two balls centrically opposed in the line of 
motion, and placed laterally to view : though the progressive of A, may be 
stopped by the kiss from P, yet, the walking rotary momentum, derived from its 
weight with the impulse given by the cue b, and denoted by the curved line c, is 
not consequently stopped also : but making the point of contact the centre o 
motion, raises the ball with a conatus, from d toward e 2 , and moreover, should 
those sections not be in the same plane, will co-operate with the horizontal or 
lateral rotation produced by this obliquity, as has been already, explaine , a 
both be expressed by the curve, it afterwards describes (see figs. 21, 22, 
Hence, a ball bitting another near to the cushion, and not far from a pot <e , 
is more frequently holed 8 in this manner, than is generally imagined ; because, 
the hitting, and kissing, are too simultaneous to be well distinguished by he 
noise: but it may be remarked, the active ball is often holed thus, (a wa '» » 
stroke being always most apt for the purpose) which would be thoug t nnprac 1 
cable, where a kiss could not take place*. Hence also, the active ball is more 
apt to bounce, than the other; and, if the view would not be thought too 
minute, it might be said, that the passive ball being quiescent, an c we » 
its weight upon the cloth, sinks lower than the ball in motion, w ic i r ’ 
fore immediately after contact; bat, the other not till aftei re ection 
the table also, by which its force is much weakened. 
When one ball hits another close to the cushion, in an acute ang e«i , 
tendency upwards from its rotary motion is much enhanced by not h.t ng bo 
exactly together ; for, then the ball, meeting, as it advances, with a htss 
* Hence the reason, why a ball played with much force against a cushion, is more 
apt to bounce up after a walking than a twisting stroke. j heine 1 
' The word held, when applied ,o the ball in this sense, ,s noi : Eughsh ,, 
the inflection of hoie, hut heid that of hold . ; hut 
sometimes used (by those who should know ' b mh are instances of a very 
with this view the fabrication can have no ex 
confined education. oro duced without the intervention of 
4 A similar effect may (notwithstanding) P so far as to admit being 
a kiss, when the passive ball lie not far from t e c us ^ not mee t the other, pro- 
hit with a considerable degree of opposition, ; ) nt somew hat extraordinary, and ac- 
vided the walking stroke be made with a vio rece j ve d, which it partly retains 
cording to the distance : for, the rotary moraen urn ^ ^all and cushion afterwards, 
after the progressive motion be destroyed by t P , o-eneration of this curious 
brings it again forward (as has been already shown) rn the gene 
result. ,| th at the active ball may only lose 
The opposition (as above) should be consi ’ * t a j s0 turned against the object 
as much as possible of the progressive, an no « - wer G f the cushion: and the 
intended, by assaulting the fixed, and moie rep ^ walking power may neithei be 
distance from the cushion should not be great, a f te r the hitching it receives 
too much wasted, nor fallen into a smoothness of 
from the passive ball, as is explained in the next p o 
