English 18K rose gold 30h power reserve chronometer Circa 1883

Rose gold precision watch by Parkinson & Frodsham
–
A fine English 18 carat rose gold hunting cased 30-hour power reserve precision pocket watch, circa 1883. ¾ Plate movement, chain and fusee, optionally key wind or crown wind, a spring detent escapement, bimetallic chronometer balance with gold screws and free-sprung duo-in-uno blued balance spring. White enamel dial with Roman hours, an outer minute track, sunk subsidiary seconds at 6 o’clock, power reserve indication at 12 and blued spade hands. The plain case with an engraved noble family crest in the front, maker’s mark HW(J). Dial signed, case numbered, movement signed and numbered, case and movement with matching numbers.
–
Diameter: 52 mm
–
Weight: 139 g
–
Signed: Parkinson & Frodsham Change Alley London
–
The duo-in-uno balance spring allows a reduction in the height of a helical spring, thus saving space in the height of a pocket chronometer movement. It is a flat balance spring converting into a cylindrical spring. It was first introduced during the 1862 Great Exhibition in Kensington, London, at the Charles Frodsham stand. According to Frodsham, it “almost certainly guarantees the most accurate performance in all positions with a perfectly poised balance” (exhibition catalogue, p. 22). This type of balance spring was supposedly invented by Mr Mairet of Baker Street and presented during the 1862 exhibition by Charles Frodsham and Mr McLennan. However, the design had already been used by Arthur Paul Walsh since circa 1860.
–
The company of partners William James Frodsham (1775-1850) and William Parkinson had its offices at 4, Change Alley in London and specialized in the production of pocket and marine chronometers. Several expeditions were equipped with their watches. Around 1847 Frodham handed the company over to his sons George and William. Parkinson & Frodsham maintained the clocks in Buckingham Palace and was appointed clockmaker to the King, the Princes of Wales and Queen Alexandra.