An eight-day oak astronomical longcase regulator by George Graham, London, No. 675, circa 1725, Known as 'Graham No.2'

The typical Graham/Shelton movement has angled shoulders to the plates which have been given a curled finish and are united by six latched knopped and stepped pillars. The lower centre of the backplate is punch marked 675. The painted brass cased weight is suspended by a silk cord which is hooked onto a projecting bracket (screwed to the frontplate) and runs through a brass pulley which has three curved crossings over a turned barrel pivoted between the plates and onto the main barrel (16 turns) which carries the great wheel and Harrison’s maintaining power with vertically pivoted stop work. All train wheels have four curved crossings. The dead beat escapement has a long shank pallet frame and jewelled pallets. The movement is secured to the heavy cast iron integral seatboard and suspension block via four screwed brackets. The Dent type, zinc-tube temperature compensated pendulum runs against a silvered pendulum scale reading 0-2 degrees.

The twelve-inch signed silvered dial has an outer minute circle enclosing a subsidiary seconds dial with observatory marks. The recessed hour subsidiary dial has a shaped blued steel hand which runs counter clockwise against an Arabic chapter. The dial is mounted to the movement by four dog-legged brackets and polished steel screws. To the right-hand side of the dial the original slot for bolt and shutter maintaining power can be seen. The minute hand is a tapering baluster shape whereas the counterpoised seconds hand is flat in section.

The 20th century blonde oak case has a moulded cornice to the sliding hood, the trunk has a glazed door and rests on a short base with moulded plinth.

Object Details

ID: ZBA2212
Collection: Timekeeping
Type: Astronomical Regulator
Display location: Not on display
Creator: Graham, George
Date made: 1725
Credit: National Maritime Museum, Greenwich, London
Measurements: 1795 x 450 (hood) x 280 (hood)
Parts: An eight-day oak astronomical longcase regulator by George Graham, London, No. 675, circa 1725, Known as 'Graham No.2'