Note 41 — Chapter I · SPECULATIVE PHILOSOPHY IN GREECE, BEFORE AND IN THE TIME OF SOKRATES.
Reading edition
Aristot. De Cœlo, ii. 9; Pliny, H.N. ii. 20.
See the Pythagorean system fully set forth by Zeller, Die Philosophie der Griechen, vol. i. p. 302-310, ed. 2nd.