Marion Brésillac, Melchior-Marie-Joseph de

MARION BRÉSILLAC, MELCHIOR-MARIE-JOSEPH DE. - Missionary, founder of the Society of African Missions, b. at Castelnaudary (Aude) on 2 Dec. 1813, d. at Freetown (Sierra Leone) on 25 June 1859.

A priest in 1838, he entered the Seminary of Foreign Missions of Paris on 2 June 1841 and, having set out for India in 1842, was elected there in 1845 titular bishop of Prusa and pro-vicar apostolic of Coimbatore. In 1854 he turned his thoughts to the abandoned peoples of Africa and was authorized by the Holy See to found a new Congregation for that purpose; thus in 1856, after many sacrifices and disappointments, the Seminary of African Missions arose at Lyons. Appointed in 1858 vicar apostolic of Sierra Leone, he landed there on 14 May 1859; but already he was falling upon the Otto de Guericke (1654) on atmospheric pressure and on gases, he carried out many experiments which he described in the Essai sur la nature de l'air (Dijon 1676). He discovered the law which today bears the names of Boyle and M.: a gas assumes a volume inversely proportional to the pressure. He published a Traité de la percussion ou choc des corps (1676) and a Traité du mouvement des eaux et des autres corps fluides (La Hire 1686, posthumous). In chemistry laboratories the "M. bottle" is still used. He was one of the first members of the Académie des Sciences founded by the minister Colbert in 1664-66. The collection of his numerous writings was published at Leiden in 1717 and at The Hague in 1740.