No.1057, Circa 1785, Case with London Hallmark for 1800
Gilt brass full plate fusee lever movement with Harrison's maintaining power and chain, going train, patented "double S" balance with two gold mean screws and two gold compensating nuts screwed onto threaded posts fixed to the free ends of the S-shaped bi-metallic strips, free-sprung helical balance spring, impulse roller made of a single piece of sapphire, the discharge roller jewelled in the usual manner, double-footed Emery-type balance bridge, with small diamond end stone, regulator type enamel dial with outer painted minute chapter and single blued steel spade minute hand, eccentric hour chapter at 12 with single blued steel spade hand, subsidiary seconds at 6, later engine turned case with the Royal Coat of Arms, signed cap held by locating pins and one screw, together with gold chain, winding key and later made fitted red velvet box, case stamped IM
52mm.