The principal parts of a watch, 1741
Detail of an engraving from Antoine Thiout l'aîné, Traité de l'horlogerie mechanique et pratique (Paris, 1741), vol. 2, pl. 34
Engraving; 9 1/2 x 15 in. (24.1 x 38.1 cm)
Thomas J. Watson Library (146.9/T34)
Thiout became a master clockmaker in Paris in 1724 and died there in 1767. His treatise, on clockmaking became a standard text of its time. His construction of a watch with a verge escapement driven by a mainspring encased in a barrel (number 7 in the print) and regulated by a cone-shaped fusee (number 8 in the print) is not greatly different from that of a seventeenth-century watch.