A two-day marine chronometer, the silvered dial signed and numbered 'T.J. Williams, 2 Bute Docks, Cardiff 1765', Roman hour numerals, gold hour and minute hands, subsidiary second dial with blue steel hand, up-and-down dial with gold hand, Earnshaw escapement, cut bi-metallic balance, blued steel helical balance spring, spring foot detent with jewelled locking stone, brass bowl gimballed in brass-bound three-tier rosewood box, the middle section with inset rectangular bone ivory plaque inscribed 'T.J. Williams, Cardiff 1765', external brass drop handles -- 3¾in. (9.6cm.) dial dia, box -- 7 1/8in. (18cm.) square