Louis Bertrand Castel, French mathematician and philosopher (born 1688)

Louis Bertrand Castel was a French mathematician born in Montpellier, who entered the order of the Jesuits in 1703. Having studied literature, he afterwards devoted himself entirely to mathematics and natural philosophy. After moving from Toulouse to Paris in 1720, at the behest of Bernard de Fontenelle, Castel acted as the science editor of the Jesuit Journal de Trévoux.

January 11 is the 11th day of the year in the Gregorian calendar; 354 days remain until the end of the year.