Claude Langlois was a French maker of precision scientific instruments and the foremost among them in the period. His instruments included draughtsman's tools like an improved pantograph, measuring instruments, and six-foot quadrants for astronomical angle measurement. He was appointed official instrument maker for French astronomers Cassini II, Cassini de Thury, Le Monnier, Maupertuis, and the Abbé de Lacaille; and held the official position of ingénieur en instruments de mathématiques for the French Académie des Sciences in 1740.