de Billy, Jacques

Alternate Name

Billy, Jacques de

Born Compiègne, (Oise), France, 18 March 1602

Died Dijon, France, 14 January 1679

Jacques de Billy was an astronomical writer, who also made contributions to mathematics, particularly number theory and Diophantine analysis. After studying humanities, he entered the Jesuit order in 1619 and completed his divinity studies, equivalent to a doctorate, in 1638. He taught theology and mathematics at a number of Jesuit colleges in northeastern France, ending his career in Dijon.

Between 1656 and 1670 Billy wrote at least three major works on astronomy in Latin: an advanced text book, a publication on eclipses entitled Tabulae Lodoicaeae(because it was dedicated to Louis XIV, the Sun King), and a book on the crisis in cometary motions. No one knew whether comets moved in straight lines, circular orbits, or some other variant, a confusion brought to the fore by the bright comets of 1664 (C/1664 W1) and 1665 (C/1665 F1). Billy also wrote Le Tombeau de...