John McLennan, London, Movement No. 9015, 52 mm, 130 g, circa 1874

A very fine lever chronometer
Case: 18k gold, polished, tiered, engraved monogram, gold dome, case maker's punch mark "GAP" (George Augustus Potter of Clerkenwell). Dial: enamel, radial Roman hours, auxiliary seconds, 30h power reserve indicator, blued spade hands. Movm.: 2/3 plate movement, keywind, frosted, gilt, chain/fusee, engraved honour cyphers, screwed chatons, English lever escapement, gold screw compensation balance, freesprung blued helical balance spring, chatoned diamond endstone on balance.