A fine, unique and historically important late 18th/early 19th century floorstanding regulator of two week duration.
Almost certainly designed and built by the great inventor and gas engineer William Murdock (1754-1839)
Of solid mahogany on an oak backboard with veneered crossbanded base, the hood of the 'drum head' type popular in Scotland in the late 18th century, set to the uppermost surface with a 'hip' to accomodate the top section of the pendulum bracket, the section of the backboard behind the hood is covered in green baize, the trunk composed of three sections of mahogany over 1 inch thick with deeply reeded carved decoration with alternating splayed edges, the centre section creating the lift-out door, located via two pins to the lower edge and locking into place at the top, set on a substantial rectangular base veneered to the front with a cross banded flame mahogany panel within a fielded surround, on a bracket base.
One piece silvered brass, 12 inches in diameter and signed in a horizontal line across the centre. The upper subsidiary dial has a counterbalanced seconds hand and is engraved with two 0-60 arabic scales divided into 100 divisions, thereby denoting that the movement beats 50 per minute.
The hour subsidiary is slightly larger and displays Roman numerals, the hand bearing a female square to take a male winding key.
The minutes are marked in arabic numerals around the periphery of the dial and marked with a central hand.
The rear of the dial is signed Donithorpe, Birmingham and carries an outer scale from 0 to 360 with a subsidiary dial marked 0-100 with the predictions Wet, Changeable, Dry and Extream (sic)
Screwed to a cast and enamelled iron seatboard, the substantial brass plates each have tall feet and shoulders, united by four large knopped pillars to a distance of 1 5/8 inch thick rather than the 2 1/4 to 2 1/2 inch thickness of standard movements. Set at the apex of the plates is a cast brass support with heart shaped lower section that carries the escapement arbor. All wheels are light and the train count is as follows:
Wheel Diam. Tooth Count Meshing pinion
Great 7.75ins. 360 36
2nd - 180 30
3rd - 144 24
'Scape - 50 -
It should be noted that the pinions are of a much higher count and the great wheel of a much larger diameter than any contemporary regulator.
Maintaining power is effected on pulling a cord inside the case; this raises one end of a lever pivotted on the front plate; at one end of the lever is a vertical rod that carries a small weighted platform, at the other is a drop arm that has a bevelled tip that meshes with a wheel of 96 teeth carried by the second arbor; the pressure on the 96 wheel is enough to power the clock while it is being wound. Duration on one winding is 15 days.
The pendulum has a total length of 61.5 inches and comprises of a wooden rod suspended by a steel suspension double screwed to the apex of a pair of cast iron supports screwed to the iron seatboard, the cylindrical brass bob is held by a regulation nut 2.08m (6ft 10ins) high.
Clocks and Watches
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