io“) 
NATURE 
[| NovEMBER I, 1906 
THE DYNAMICS 
OLLOWING up interesting volume on 
“Great Batsmen,’’ the accomplished authors of 
“Great Bowlers and Fielders’’ have practically com- 
pleted all that action photography can teach us re- 
garding the methods of great cricketers. The present 
handsome volume with its 464 action photographs 
registers for all time the successive positions of the 
body in the act of bowling of some of the most 
celebrated bowlers of our day, and also certain very 
characteristic attitudes of a number of our best 
fielders. From the purely cricketing point of view 
the book must ever be of the most enthralling interest, 
not because it establishes any funda- 
OF BOWLING.* 
their 
, 
with the horizontal, it is clear that there is very 
little chance of a cricket ball beginning its swerve to 
right or left for the same reason that a golf ball is 
sliced or pulled. How, then, is the swerve to be 
explained? The matter crops up at intervals through- 
out the book, and is discussed at some length by Mr. 
Spofforth; but with all due regard to his authority 
as one of the greatest bowlers of all time, it is 
difficult to accept his explanation as in every respect 
sound. He says that ‘‘a ball which has check spin 
(that is, under-spin) on it, loses it through friction 
against the air during its flight; at the moment this 
occurs the ball slips the cushion of air it has made, 
especially in between the seams. What leads me to 
mentally new principle in the art of high- 
class bowling, but because it proves the 
wonderful variety of method by which 
different individual bowlers effect practi- 
cally the same result. The movements of 
the body, arm, wrist, hand, and fingers 
are all coordinated to the one end of 
imparting to the ball a definite combin- 
ation of translation and spin. It does not 
always happen that the bowler hits off 
the exact combination aimed at, but when 
he does the future progress of the ball 
through quiet air and off a good pitch is 
absolutely definite. There is no difficulty 
in understanding the dynamics of the 
“ breals ’’; the problem is simply that of a 
rotating sphere impinging obliquely on 
a rough surface, and is familiar to every- 
one who has handled a billiard cue with 
intelligence. The point of interest to the 
would-be bowler is how it is effected. 
This is discussed at considerable length 
in distinct parts of the book contributed 
by Messrs. F. R. Spofforth, B. J.T: 
Bosanquet, and R. O. Schwarz. The 
introductory chapter by the ‘* Demon 
Bowler” (to whom the bool is dedicated) 
is capital reading. It is, indeed, rather 
to be studied than read, and the same re- 
mark applies to Mr. Bosanquet’s lucid 
and scientific discussion of the ‘ off- 
breaking leg-break.”’ 
At the very outset it is obvious that 
no bowler can give to a cricket ball 
anything like the combined velocity 
and spin which can be so easily com- 
municated to a golf ball, or even to 
a tennis ball. The comparative lightness 
of the latter enables the player to give it 
sufficient spin (with velocity) so as to call 
into action the differential air pressure, 
producing evident swerve. Tait, in his 
discussion of the  golf-ball flight, 
showed that this swerving force (which 
acts at right angles to the plane containing the 
velocity and the axis of spin) may be taken as being 
proportional to the product of the translational and 
angular speeds. He estimated that it might attain 
a value equal to about four times the weight of the 
ball. In the case of the cricket ball it is doubtful 
if the deviating force due to air pressures acting on 
the progressing and rotating ball could ever become 
more than a small fraction of the weight. Then, as 
the rotation takes place in all over-hand delivery 
about an axis which males at the most a small angle 
1 ““Great Bowlers and Fielders. Their Methods at a Glance. By G. W. 
Reldam and C. B. Fry. Pp. xv+547; illustrated. (Macmillan and Co., 
Ltd., 1906.) Price 21s. net. 
NO. 1931, VOL. 75] 
Fic. 1.—W. Rhodes at the beginning of his final swing. From ‘* Great Bowlers and 
Fielders.” 
this belief is that it is almost impossible to swerve 
unless the seam of the ball is up and down. The 
check spin keeps the seam vertical until the air- 
resistance causes the spin to cease altogether. At 
this point, especially if the ball has an upward 
tendency and the earth’s power of attraction is 
asserting itself, the swerve will be great. To swerve, 
the ball must have some spin on it, but not much. 
If it has great spin it will never lose it in time to 
swerve, and I maintain that at the actual time of 
swerving the ball has ceased to spin, or nearly so.” 
Further on he says that he has ‘‘ never seen any 
bowler swerve with the wind,’’ that ‘‘a bowler 
swerves more while the ball is new,’’ that he does 
