The Wealth of Nations by Part 1 Chapter 10 Page 105

city to so famous a teacher, who taught, too, what was at that time the most fashionable of all sciences, rhetoric. He must have made, therefore, by each course of lectures, a thousand minae, or L3333 6s. 8d. A thousand minae, accordingly, is said by Plutarch in another place, to have been his Didactron, or usual price of teaching. Many other eminent teachers in those times appear to have acquired great fortunes.

Gorgias made a present to the temple of Delphi of his own statue in solid gold. We must not, I presume, suppose that it was as large as the life. His way of living, as well as that of Hippias and Protagoras, two other eminent teachers of those times, is represented by Plato as splendid even to ostentation. Plato himself is said to have lived with a good deal of magnificence. Aristotle, after having been tutor to