A history of Greek mathematics - Wilbourhall.org

XVI
SOME HANDBOOKS
The description of the handbook on the elements of
astronomy entitled the Introduction to the Phaenomena and
attributed to Geminus might properly have been reserved
for this chapter. It was. however, convenient to deal with
Geminus in close connexion with Posidonius ; for Geminus
wrote an exposition of Posidonius's Meteorologica related to the
original work in such a way that Simplicius, in quoting a long
passage from an epitome of this work, could attribute the
passage to either Geminus or ' Posidonius in Geminus
'
; and it
is evident that, in other subjects too, Geminus drew from, and
was influenced by, Posidonius.
The small work De motu circulari corporum caelestium by
Cleomedes (KXeofirjSovs kvkXlktj Oecopfa) in two Books is the
production of a much less competent person, but is much more
largely based on Posidonius.
This is proved by several references
to Posidonius by name, but it is specially true of the
very long first chapter of Book II (nearly half of the Book)
which seems for the most part to be copied bodily from
Posidonius, in accordance with the author's remark at the
end of Book I that, in giving the refutation of the Epicurean
assertion that the sun is just as large as it looks, namely one
foot in diameter, he will give so much as suffices for such an
introduction of the particular arguments used by 'certain
authors who have written whole treatises on this one topic
(i. e. the size of the sun), among whom is Posidonius '. The
interest of the book then lies
mainly in what is quoted from
Posidonius ; its mathematical interest is almost ail.
The date of Cleomedes is not certainly ascertained, but, as
he mentions no author later than Posidonius, it
is permissible
to suppose, with Hultsch, that he wrote about the middle of