Lettres d'Auguste Comte a M. Valat, Professeur de Mathématiques 1815-1844. Paris: Dunod. July 1870.

vii, 350[2] pp; all edges gilt. Contemporary good-quality dark green morocco gilt by P. Delacour, slightly rubbed, a handsome copy. First edition. The change in Comte's personal feelings toward Saint-Simon can best be followed in his correspondence with his friend Valat (1870), which shows how much he was initially stimulated by Saint-Simon and how he later withdrew from the relationship. One difference was revealed by Comte himself in his correspondence with Valat when he asserted that Saint-Simon's advocacy of political action before the scientific system of positivism had been sufficiently developed was putting the cart before the horse.