Voltaire, as is well known, went sadly wrong over Aristarchus Philosop/zz'que, s.v. He said that Ari starchus 'is so obscure that Wallis was obliged to annotate him from one end to the other, in the effort to make him intelligible', and fur her that it was very doubtful whether the book attributed go tristarchus was really by him. Voltaire (misled, it is true, by a wrong reading in a passage of Plutarch, De fade in orbe lunae, c. 6) goes on to question whether Aristarchus had ever propounded the heliocentric hypothesis; and it is clear that the treatise which he regarded as suspect was Roberval's book, and that he confused this with the genuine work edited by Wallis. Nor could he have looked at the latter treatise in any but a very superficial way, or he would have seen that it is not in the least obscure, and that the commentary of Wallis is no more elaborate than would ordinarily be expected of an editor bringing out for the first time, with the aid of mss. Not of the best, a Greek text and translation of a mathematical treatise in which a number of geometrical propositions are assumed without proof and therefore require some elucidation.