Spring detent escapement watch by John Arnold, in a later silver case. White enamel dial with a subsidiary seconds dial and gold spade hands. Jewelled movement with diamond endstone.

The original escapement has a later conversion to Earnshaw's spring detent arrangement, and has a later type of two-arm compensation balance.

Signed 'John Arnold & Son, London. Invenit & fecit 485/786'. Movement c.1794, case hallmarked for 1840, casemaker's mark 'CBH' and stamped 485.

This watch was made for HRH the Duke of Sussex, but was substantially rebuilt c.1840. It was used from 1834 to carry correct time from the Greenwich Observatory to the London horological trade by John Henry Belville, then from 1856 – 1892 by his widow and thereafter by their daughter Ruth, until she retired in 1940. Ruth Belville knew it as ‘Mr. Arnold’.

Clockmakers Museum No. 429