English fine large silver pair cased verge watch Circa 1700

Fine and large silver pair cased verge watch
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An English fine and large silver pair cased verge watch, circa 1700, gilded full plate movement, verge escapement, decoratively pierced and engraved masked balance cock decorated with a bird, foliage and a basket of fruit, silver regulator plate with blued steel center and decorative gilded pointer in the form of a hand, fusee and chain, tulip pillars, signed Will Bertram, London.
Silver champlevé dial, Roman numerals, fleur-de-lys half-hour divisions, outer Arabic minute ring, gilded outer border, blued steel tulip and poker hands, elaborate central cartouches, signed Bertram, London.
Plain inner case, the back with winding aperture, split bezel for glass retention, plain outer case, both cases with maker’s mark WB incuse, probably for William Bertram.
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Diameter: 59 mm
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Signed: Will Bertram London
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This unusually large watch has an especially interesting movement. Whilst the escape wheel has a normal six-leaf pinion, the train has one more wheel than usual. The train’s wheels have a high tooth count and the pinions have twelve leaves. Rather than increasing the running time of the piece, this arrangement should result in a better transmission of power, thereby creating a more reliable watch.

William Bertram (also Bartram) was born c. 1663. Initially apprenticed to Samuel Horne, he transferred to the case maker Samuel Bowtell (see lot 6 in this sale) after June 1681, and was freed in 1684. Interestingly, a Clockmakers’ Company minute of 1708 records that Bertram was excused stewardship of the Clockmakers’ Company on account of being “at present busy on the Queen’s business”.