Note 7 — BOOK II.

Xenophon. (Essay on The Revenues, IV., 30). "I think, however, that I am able to give some advice with regard to this difficulty also (the risk of opening new mines), and to show how new operations may be conducted with the greatest safety. There are ten tribes at Athens, and if to each of these the State should assign an equal number of slaves, and the tribes should all make new cuttings, sharing their fortunes in common, then if but one tribe should make any useful discovery it would point out something profitable to the whole; but if two, three, or four, or half the number should make some discovery, it is plain that the works would be more profitable in proportion, and that they should all fail is contrary to all experience in past times." (Watson's Trans. p. 258).