Fine English deck chronometer in brass case Circa 1798

Very fine and early extremely rare deck chronometer
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A numbered very fine early and extremely rare deck chronometer, made by Brockbanks in London, England, circa 1798. The wooden box is missing but the numbered open faced cylindrical brass case has a bayonet locking. The white enamel dial has black Roman hour numerals a subsidiary seconds dial with black Arabic numerals at six o’clock and the original gold hour hand and a minute hand, which was added later. The movement has a very early chronometer escapement with helical hairspring and a diamond end stone, a special chronometer balance with trapezoidal and cylindrical weights.
Dial and case signed.
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Signed: Brockbanks, London
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This is one of Brockbanks earliest chronometers, made before 1800, the watch was part of one of the most important European chronometer collections.
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Brockbanks
John Brockbank worked in Old Jewry and later Cooper’s court in London. He was apprenticed as a watchmaker by Joseph Harding in London from 1761. “Brockbanks” was the signature the brothers John and Myles Brockbank of London used for their watches, which were usually excellent pocket and marine chronometers. The brothers were outstanding early chronometer makers and members of the Clockmakers’ Company. Myles was admitted to the Clockmaker’s Company in 1776 and John in 1779. They often worked with prominent makers like Thomas Earnshaw, who claimed that he showed them his version of the spring detent escapement and Peto, who developed a variant of the spring detent escapement – the “cross detent”. Some of the existing Brockbank chronometers are fitted with this type of escapement and fetch high collector prices today. After Myles death in 1821, the brothers were succeeded by nephews, also named John and Myles, who traded as John Brockbanks & Company. From 1815 to 1835 they took Samuel Elliot Atkins as a partner and the firm was called “Brockbank & Atkins”, still at 6 Cowper’s Court.