LOUIS DU, natural son of Jean Louis de Montcalm Seigneur de Candiac, and a widow of rank belonging to Rouergue, was born at Nismes in 1676. His attention was first bestowed on jurisprudence; but he afterwards occupied himself exclusively with the study of mathematics, philosophy, and languages. Father Malebranche cultivated his acquaintance, and esteemed his virtues. His appearance was severe, but his temper was tranquil, and he had a lively, fertile imagination. His mind was active, full of resources, and methodical. We are indebted to his industry for the typographical bureau. This invention is the more ingenious, as it presents the tedious parts of education, namely, reading, writing, and the elements of language, to the youthful mind as a delightful entertainment; and many people in France, both in the capital and in the provinces, have adopted it with success. After he had conceived the idea of this invention, he made the first trial of it on the young Candiac, who was remarkable for understanding, even in his earliest years. Dumas conducted his pupil to Paris and the principal cities in France, where he was universally admired. This prodigy was carried off in the year 1726, before he had attained the age of seven, and his loss nearly deprived Dumas of his reason. A dangerous illness was the consequence; and he would have died of want, if a gentleman had not taken him from his garret and entertained him in his own house. Dumas afterwards retired with Madame de Vaujour about two leagues from Paris, and died in the year 1774, aged sixty-eight. He was a philosopher both in genius and character. His works are, 1. L'Art de transposer toutes sortes de Musiques sans être obligé de connaitre, ni le temps, ni le mode, Paris, 1711, in 4to; 2. Bibliothèque des Enfans, Paris, 1733, in four parts, a treatise in which he has explained the system and economy of his typographical bureau; 3. Mémoires de l'Ecosse sous le règne de Marie Stuart, translated from the English of Crawford.