Collas a learned French missionary and astronomer, of the Jesuit order, was borni at Thionville about 1731. He taught mathematics at the University of Lorraine, and in 1767 went to Pekin, where he acted as mathematician to the emperor of China. He died January 22, 1781, leaving several very important sketches, inserted in a collection of the Memoires upon the Chinese, viz.: Etat des Reparations et Additions Faites a l'Observatoire Vati depuis Longtemps dans le Maison des Missionnaires Franvais a Pekin, and others. See Hoefer, Nouv. Biog. Generale, s.v.; Biog. Universelle, s.v.