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Maker, George Jamison, Charing Cross, London, England, c. 1800. Movement net 18"h x 8"diameter, overall with base 22"h x 10.5"diameter. Two plane anchor escapement with divided lift, i.e. the two pallets are in different planes relative to each other. One half second pendulum with engraved silvered Earth globe as the bob. Rack and pinion striking on the hour. Two train chain fusee, with Harrison maintaining power, eight day duration. Silvered chapter rings and fire gilt ormolu decorations and tripod frame.

This rear photo of the perpetual calendar shows the cam necessary to take into account the leap year which enables the perpetual function.

The vertical arbor at the base of the photo is connected to the minute annular ring. This in turn through the pair of geared wheels at the center of the photo drives the Greenwich dial at the apex of the clock.

A close up of the pendulum bob made as an engraved, silvered globe

A detail of one of the compass points and associated securing brackets.

In this picture one can see part of the escapement wheel in the lower foreground. Notice how the teeth are angled, much like a turbine fan blade.

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