An elaborately decorated pocket chronometer, c.1827 by Harrison

Made by Harrison, Royal Exchange. Details of the maker are unknown. The movement is engraved 'Maker to the Board of Longitude'. This may have been true; equally however it may have been an attempt to enhance the prestige of the watch by association. John Harrison (1693-1776) had been the first man to construct a successful marine chronometer and thus won the 20,000 pounds prize offered by the Board of Longitude.

The movement is fusee driven with Earnshaw's spring detent escapement. The bi-metallic compensated balance has three arms rather than the more usual two but otherwise is an Earnshaw type with segmental brass weights capped in steel. The balance spring is spiral - the helical spring was abandoned probably in order to reduce the height of the cock and thus the thickness of the watch.

The extensive use of gold in a variety of decorative techniques creates an ugly impression. The heavy gold pair case has a chased band and pendant while the back is engine turned. The gold dial is mechanically spotted with raised polished gold numerals. An outer chased floral band is of gold, and even the hands are of gold, giving a confusing appearance to the dial.

Watches of this type were manufactured principally for export to Spain and South America where the conspicuous wearing of gold ornaments conferred social prestige. They also achieved a certain popularity in England particularly in northern counties and may have been a way of protecting assets at a time when bank failures were commonplace.

Accession No. 1992.8.33

A marine chronometer in a mahogany box, c.1830 Riachard Hornby, Liverpool

The movement is fusee driven with Harrison's maintaining power. As with the best chronometers, the wheel train has high count pinions, i.e. pinions with large numbers of leaves (teeth) in order to minimise friction. The escapement is Earnshaw’s spring detent with bi-metallic balance and segmental weights. The movement is mounted in gimbals so that it remains horizontal and thus undisturbed by the motion of the ship.

The practical nature of this timepiece means that decorative features are kept to a minimum. The silvered dial is finely engraved with a sweeping signature. The box is in solid mahogany, bound in brass.

The development of precision timekeeping instruments for use at sea, making it possible for a vessel to calculate its longitudinal position anywhere in the world, dominated eighteenth century horology.  English success in this field led in the nineteenth century to many specialist chronometer makers setting up their business in sea ports. Chronometer manufacturing was the one area of the horological industry largely unaffected by foreign competition during this century.

Accession No. 1992.1.237

A 28 day duration longcase regulator by Georeg Graham, London.c.1745

Despite the conventional longcase dial of this clock, the movement with high count pinions and dead beat escapement is that of a regulator. The hands are counter-weighed by additional brass segments on the motion work, and the winding barrel has stop work as a fusee to prevent over-winding. Maintaining power is a bolt and shutter and, suprisingly, the pendulum has a brass rod with massive lenticular bob.

The delightfully austere case of this clock is veneered in figured walnut over an oak carcass. The 12" square dial has separate chapter, seconds and date rings and the dial back is now, unusually, silvered, but was orginally gilt. The gilt spandrels are of the mask and foliate style.

This clock, designed for serious accuracy, would have been the most expensive type available at the time. Regulators were used by astronomers but the 'domestic' dial and case suggests that this was designed for more personal use.

Accession No. 1992.1.10