CLEOMEDES 
237 
sisting of an elaborate refutation of Epicurus and his followers, 
who held that the sun is just as large as it looks, and further 
asserted (according to Cleomedes) that the stars are lit up as 
they rise and extinguished as they set. The chapter seems to 
be almost wholly taken from Posidonius; it ends with some 
pages of merely vulgar abuse, comparing Epicurus with Ther 
sites, with more of the same sort. The value of the chapter 
lies in certain historical traditions mentioned in it, and in the 
account of Posidonius's speculation as to the size and distance 
of the sun, which does, as a matter of fact, give results much 
nearer the truth than those obtained by Aristarchus, Hippar 
chus, and Ptolemy. Cleomedes observes (1) that by means of 
water-clocks it is found that the apparent diameter of the sun 
is 1/750th of the sun’s circle, and that this method of 
measuring it is said to have been first invented by the 
Egyptians; (2) that Hipparchus is said to have found that 
the sun is 1,050 times the size of the earth, though, as regards 
this, we have the better authority of Adrastus (in Theon of 
Smyrna) and of Chalcidius, according to whom Hipparchus 
made the sun nearly 1,880 times the size of the earth (both 
figures refer of course to the solid content). We have already 
described Posidonius’s method of arriving at the size and 
distance of the sun (pp. 220-1). After he has given this, Cleo 
medes, apparently deserting his guide, adds a calculation of 
his own relating to the sizes and distances of the moon and 
the sun which shows how little he was capable of any scien 
tific inquiry. 1 Chap. 2 purports to prove that the sun is 
1 He says (pp. 146. 17-148. 27) that in an eclipse the breadth of the 
earth’s shadow is stated to be two moon-breadths ; hence, he says, it 
seems credible {mdavov) that the earth is twice the size of the moon (this 
practically assumes that the breadth of the earth’s shadow is equal to 
the diameter of the earth, or that the cone of the earth’s shadow is 
a cylinder!). Since then the circumference of the earth, according to 
Eratosthenes, is 250,000 stades, and its diameter therefore ‘ more than 
80,000 ’ (he evidently takes tt = 8), the diameter of the moon will be 
40,000 stades. Now, the moon’s circle being 750 times the moon’s 
diameter, the radius of the moon’s circle, i.e. the distance of the moon 
from the earth, will be |th of this (i.e. tt = 8) or 125 moon-diarrfeters; 
therefore the moon’s distance is 5,000,000 stades (which is much too 
great). Again, since the moon traverses its orbit 13 times to the sun’s 
once, he assumes that the sun’s orbit is 13 times as large as the moon’s, 
and consequently that the diameter of the sun is 13 times that of the 
moon, or 520,000 stades and its distance 13 times 5,000,000 or 65,000,000 
stades!