Watch by William Koster, Netherlands, 1725–1750

Record summary

Held and catalogued by Musée du Louvre, Paris (object number OA 6224), this is a watch by William Koster, made in Amsterdam, Netherlands, dated 1725–1750. The Atlas places it in the Early Modern Horology period (1600 – 1750) of its Pocket Watches collection. Materials and techniques recorded by the source: diamond, brass. Recorded dimensions: height 5,4 cm; width 4,3 cm; thickness 2,5 cm. The record is illustrated with 6 photographs.

Assembled from the source record's structured fields. Dates and attributions are given as the source states them; where a field is missing the Atlas leaves it blank rather than estimating.

Catalogue description

Atlas type guide

Pocket watches

The pocket watch was the dominant personal timekeeper from the late seventeenth century until the First World War. Its development tracks the history of the escapement: verge watches with fusees until the late eighteenth century; Thomas Mudge's lever escapement (c. 1755) and the cylinder escapement popularised by George Graham and later by Swiss makers; and the Swiss and English lever watches of the nineteenth century. Lépine's bar-bridge calibre and keyless winding made watches thinner and easier to use.

Industrialisation transformed the trade: American factories such as Waltham (from 1850) and Elgin produced interchangeable parts by machine, and Swiss makers responded with their own mechanisation after the 1876 Philadelphia Exhibition. By 1900 a reliable watch was affordable to millions; the finest makers continued to produce complications and precision watches.

General guidance written by the Atlas editors about this kind of object. It is not a statement about this particular piece; for that, rely on the source record above and on physical examination.

Read next:Verge escapementDetached lever escapementIdentification Centre