Note 100 — BOOK II. AN ACCOUNT OF THE WORLD AND THE ELEMENTS.

The account of the elements, of their nature, difference, and, more especially, the necessity of their being four, are fully discussed by Aristotle in various parts of his works, more particularly in his treatise De Cœlo, lib. iii. cap. 3, 4 and 5, lib. iv. cap. 5, and De Gener. et Cor. lib. ii. cap. 2, 3, 4 and 5. For a judicious summary of the opinions of Aristotle on this subject, I may refer to Stanley’s History of Philosophy; Aristotle, doctrines of, p. 2. l. 7, and to Enfield, i. 764 et seq. For the Epicurean doctrine, see Lucretius, i. 764 et seq.