10 
NATURE 
[| NOVEMBER I, 1906 
help here. The main fact is that all swervers project 
the ball with the seam as nearly as possible in a 
vertical plane. In the grip the fingers do not touch 
the seam, although in some cases the thumb does. 
But evidently there is little purchase on the ball, 
which is projected with comparatively little spin. If 
cross wind is not absolutely essential it certainly 
greatly facilitates the swerve. With some bowlers 
the swerve is evident from the start; with others it 
begins to appear only during the latter half of the 
trajectory. The seam is really a roughened zone on 
which the air may be supposed to exert a greater 
frictional torce than on the other parts of the ball, 
especially if the ball be new. With seam vertical and 
a cross wind blowing, certain definite dynamical 
effects will follow. One of these will be a tilting of 
the axis of rotation, a tilting which will, however, 
take place very slowly when the spin is excessive. 
This suggests the question, does the seam remain 
vertical throughout the flight of a swerving ball? 
The point might be settled by bowling a swerving 
ball against a blackened surface and finding which 
part of the ball first came in contact with the surface. 
That, however, is outside the purpose of the volume. 
The questions of swerve and break have much 
scientific interest, but they cover only a part of the 
whole; and from a cricketing point of view much 
might be said, not only as to the excellence of the 
pictures, but as to the instruction conveyed by them 
and by the accompanying letterpress. Mr. Beldam has 
aimed at getting a succession of positions of each 
bowler, from the beginning of the final stride before 
delivery to the follow through after the ball is de- 
livered. In a few cases the series begins even sooner. 
Where so much is excellent and characteristic it is 
difficult to choose, but here we have reproduced two 
pictures which will show to what a high degree of 
perfection Mr. Beldam has carried his photographic 
art. The one represents W. Rhodes at the beginning 
of his final swing, and is chosen partly because of the 
perfection with which the grip of the ball is indicated. 
The other is taken from the last quarter of the book, 
which treats of fielders, and is a remarkably fine 
picture of J. Tunnicliffe securing a ‘‘ wide, high up, 
right-handed catch in the slips.”’ This is one of a 
series showing Tunnicliffe bringing off difficult 
catches in most extraordinary attitudes. 
Like its predecessor, ‘‘ Great Batsmen,’’ this volume 
is a treasure-house of portraits of many of the most 
conspicuous cricketers of to-day. It is further 
beautified by a good coloured reproduction of the 
portrait of F. R. Spofforth painted by H. S. Tuke, 
AURA. CeGK 
THE POSITION OF AGATHOCLES DURING 
THE ECLIPSE OF z.c. 310 AUGUST. 1. 
(@y B.c. 310 August 14 Agathocles left Syracuse by 
sea; at eight o’clock on the following morning 
he saw a total eclipse of the sun. His exact position 
is therefore of extreme interest to astronomers. 
Unfortunately, the course that Agathocles steered is 
not directly stated. The present paper is an attempt 
to piece together the various clues contained in the 
narratives. 
We may first briefly glimpse at the way in which 
Airy handled this question (Phil. Trans., 1853, p. 188). 
It appears that on August 20, after a six days’ voyage, 
Agathocles landed in Africa at a place that Airy 
identifies with Alhowareah. Supposing that he went 
direct, the distance travelled in six days would be 
200 miles; if he went round Sicily the distance would 
be 330 miles. Airy therefore marks off on a map 
thirty-three miles in a southerly direction and fifty- 
NO. 1931, VOL. 75 | 
| to rowing than the Syracusans (Justin). 
five miles in a northerly direction. He labels these 
positions as the ‘ possible southern position ’’ and 
“possible northern position,’’ and he states in the 
text that the northern position is the more probable, 
partly because the distance is greater, and partly 
because the provision ships mentioned in the narrative 
probably came from Gela in the south. 
To us, however, it appears totally incredible that 
Agathocles, after running from a superior enemy for 
twenty-four hours or thereabouts, should have been 
within fifty-five miles of his starting point. We will 
now proceed with our own attempt to reconstruct the 
situation. 
The first point is that Agathocles started early in 
the morning, and to that extent had the more time 
in which to get to a distance from Syracuse. This is 
proved by an expression in the narrative of 
Diodorus :—‘‘ After six days and an equal number of 
nights, as dawn appeared ”’ (€€& & npépas kai tas tous 
vukTas avT@v TAEVTYT@Y, UTopawwovans THs ew). We have 
no wish to strain this expression to imply that he 
started at the exact instant of dawn on August 14. 
It clearly, however, implies that Agathocles was at 
sea for so great a part of August 14 as to render the 
phrase ‘‘six days and an equal number of nights ” 
more exact than ‘‘ five days and six nights.”’ 
Our second point is that Agathocles had a_ fair 
wind. We prove this as follows :—The Carthaginian 
fleet was blockading Syracuse, when some provision 
ships appeared in the neighbourhood. The Cartha- 
ginians went to attack the provision ships; Agathocles 
escaped from Syracuse; the Carthaginians left the 
provision ships and pursued Agathocles; the pro- 
vision ships then entered Syracuse. It must be re- 
membered that warships could be rowed, and that 
merchant vessels could only sail; and also that so 
late as the time of Nelson the power of beating to 
windward practically did not exist. The mere fact 
that the provision ships entered Syracuse therefore 
establishes the fact that the wind was favourable, 
both for the provision ships approaching Syracuse 
and for Agathocles flying from Syracuse; but other 
considerations will prove the same point. The 
Carthaginians, by leaving the provision ships when 
they had all but seized them (mAnotov {dn Tv poprnyav 
évres), clearly had no intention of letting Agathocles 
escape. Before going to attack the provision ships 
they probably argued that the occasion would find 
Agathocles utterly unprepared, and ‘that by the time 
he had put his men and stores on board they would 
themselves be back again. Now a stern chase 
is proyerbially a long chase (and, moreover, would 
have taken them out of sight of Syracuse), and the 
Carthaginians could not have entertained hopes of 
getting back in time unless the provision ships lay 
to windward of them. Even as it was, Agathocles 
was ready for his opportunity. His men, we are 
expressly told, had been on board for some days 
(wAnpaoas EEnkovta vais emeTHpeL Kalpov oikeloy mpos TOV 
éxmAovv), and he got to sea at exactly the right 
moment, that is to say, when the Carthaginians had 
all but reached the provision ships. 
Agathocles therefore had a fair wind, and to that 
extent it is the more probable that he was at a con- 
siderable distance from Syracuse by the next morn- 
ing. 
Two minor points may here be noticed, though they 
are not essential to our main case. When the sixth 
day dawned Agathocles found himself in the vicinity 
of a Carthaginian fleet, not necessarily the same one. 
He rowed hard towards shore, and by virtue of a long 
start arrived first, although the Carthaginians were 
rapidly gaining on him, being more accustomed 
Possibly, 
