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SOME HANDBOOKS 
We next have (chap. 31, p. 178) an allusion to the systems 
of Eudoxus, Callippus and Aristotle, and a description 
(p. 180 sq.) of a system in which the ‘carrying’ spheres 
(called ‘hollow’) have between them ‘solid spheres which’by 
their own motion will roll (dveXigovcn) the carrying spheres in 
the opposite direction, being in contact with them These 
‘solid’ spheres (which carry the planet fixed at a point on 
their surface) act in practically the same way as epicycles. 
In connexion with this description Theon (i.e. Adrastus) 
speaks (chap. 33, pp. 186-7) of two alternative hypotheses in 
which, by comparison with Chalcidius, 1 we recognize (after 
eliminating epicycles erroneously imported into both systems) 
the hypotheses of Plato and Heraclides respectively. It is 
this passage which enables us to conclude for certain that 
Heraclides made Venus and Mercury revolve in circles about 
the sun, like satellites, while the sun in its turn revolves in 
a circle about the earth as centre. Theon (p. 187) gives the 
maximum arcs separating Mercury and Venus respectively 
from the sun as 20° and 50°, these figures being the same as 
those given by Cleomedes. 
The last chapters (chaps. 37-40), quoted from Adrastus, deal 
with conjunctions, transits, occultations and eclipses. The 
book concludes with a considerable extract from Dercyllides, 
a Platonist with Pythagorean leanings, who wrote (before the 
time of Tiberius and perhaps even before Varro) a book on 
Plato’s philosophy. It is here (p. 198. 14) that we have the 
passage so often quoted* from Eudernus : 
‘ Eudernus relates in his Astronomy that it was Oenopides 
who first discovered the girdling of the zodiac and the revolu 
tion (or cycle) of the Great Year, that Thales was the first to 
discover the eclipse of the sun and the fact that the sun’s 
period with respect to the solstices is not always the same, 
that Anaximander discovered that the earth is (suspended) on 
high and lies (substituting kcTtcu for the reading of the manu 
scripts, KLvdrou, moves) about the centre of the universe, and 
that Anaximenes said that the moon has its light from the 
sun and (explained) how its eclipses come about’ (Anaxi 
menes is here apparently a mistake for Anaxagoras). 
1 Chalcidius, Comm, on Timaeus, c. 110. Cf. Aristarchus of Samos, 
pp. 256-8.