FERDINAND BERTHOUD (1727-1807), Swiss chronometermaker, was born at Plancemont, Neuchatel, in 1727, and settling in Paris in 1745 gained a great reputation for the excellence and accuracy of his chronometers. He was a member of the Institute and a fellow of the Royal Society of London, and among other works wrote Essais sur l'horlogerie (1763). He died in 1807 at Montmorency, Seine et Oise. He was succeeded in business by his nephew, Louis Berthoud (1759-1813).