The watch movement has a verge escapement and a chain-driven fusee to regulate the power of the mainspring. The face has a differential dial: the single hand indicates the minutes around the circumference of the dial and shows the hours on the small central disc, which revolves so that the appropriate hour is below the hand.
Around 1700 there was considerable variation in the layouts of dials. Watchmakers experimented to find the most legible way of showing minutes as well as hours. This increase in precision was made possible by the introduction of the balance spring in the 1670s, which gave watches much greater accuracy.
James Markwick (sometimes Marquet) was apprenticed in 1656, became a Freeman in 1666, and worked until the early 1700s. He appears to have had a fiery character. In September 1677 he was fined for abusing the Master of the Clockmakers' Company at a feast. In 1686 he refused to pay a fine for absence from a Clockmakers' Company court (meeting of senior members) and left 'in an abrupt and angry manner'.
Materials & Techniques
Tortoiseshell comes from various species of marine turtle. It is thermoplastic and can be softened by hot water or steam then pressed into shape. Piqué work is created by studding the surface with small, profiled silver rods to give a spangled effect. The technique was introduced to Britain in the late 17th century by Huguenot craftsmen.
The bow (the suspension oval at the top of the watch) is a late 18th-century replacement.