Jean le Rond d'Alembert was born in November 1717, and was exposed as a foundling near the church of St Jean le Rond in Paris, and thus called by the name of the parish. The commissary of the district, taking pity upon the infant's apparently dying condition, instead of sending it to the hospital, where it would have inevitably died, gave it to be nursed by the wife of a poor glazier. In a few days, however, a person named D'Estouches, a commissary of artillery, came forward, acknowledged the child, and made provision for its support. The habits of foreign life are generally so scandalous, that they can scarcely be alluded to without offending our sense of delicacy. The mother of this infant was an unmarried woman, living in the very highest circles of Paris, the sister of Cardinal Tencin, archbishop of Lyons. This woman thus added to her vice the cruelty of exposing her unfortunate offspring to die of cold and hunger in the streets. It does not appear that her profligacy, though notorious, ever affected her position in society. Her coteries were as gay, her circle was as complete, and her rank as high, as ever. In the Paris of those days, "throwing the first stone" was unheard of; its reaction would have been an avalanche; there was no scandal where there was no concealment; there was no crime where there was no conscience; and thus danced the world away, until the scourge of a higher power swept the whole noblesse of France into beggary and exile. D'Alembert seems to have taken his surname from that of his nurse, and was sent, when twelve years old, to the College of La Nation, then in the possession of the Jansenists. There he learned mathematics. On leaving the college, he returned to the glazier's house, there had one room for his bedroom and study, lived on the family fare, supported himself on a pension of £50 a-year left to him by his father, and in that house lived for forty years. He once made an abortive attempt to study the law and medicine, but soon grew weary of both, and returned to mathematics, for which he had a decided predilection. His application to this study, however, by no means pleased the homely sense of his old nurse. "You will never be any thing better than a philosopher," was her usual saying. "And what's a philosopher?--a fool, who wears out his life, to be spoken of after he is dead."