English 34 minute carrousel pocket chronometer Circa 1902

Silver open-faced chronometer with carrousel
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An exceptional English silver open-faced keyless 34-minute carrousel pocket chronometer, circa 1902.
Frosted gilt 3/4 plate movement, 34-minute carrousel with spring detent escapement, free-sprung bimetallic compensation balance, plain balance cock with diamond endstone, signed and with engraved Admiralty broad arrow.
White enamel dial with a slightly recessed centre, Roman hours and Arabic minutes, outer minute ring calibrated to fifths of a second, blued steel spade hands and centre seconds. Plain polished hinged case back. Polished hinged silver cuvette, case back and cuvette Hallmarked London 1902 and with maker’s mark WB in a cameo for William Bullock. Comes with a wooden deck box containing a brass inner case with screwed-down bezel to hold the watch, hinged wooden lid.
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Diameter: 57 mm
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Signed: Richard Thorneloe 13 Stanton Street Coventry
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At the Greenwich observatory trial of 18th June 1904 to 7th January 1905, the present watch headed the list. This was a remarkable achievement and was a testament to the watch’s outstanding performance during the rigorous 29-week trials. The tests were undertaken on behalf of the Admiralty who paid considerably more for those watches which were well placed. The Royal Observatory’s Ledger of Receipts and Issues of Chronometers record that this chronometer, was purchased in March 1905.
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The movement has a 34-minute carrousel carriage for, most unusually, a spring detent escapement. Bahne Bonniksen, a Dane who spent most of his life in Coventry, took out his carrousel patent (No. 21421) in 1892. Bonniksen modified the original carrousel design, which revolved every 52½ minutes so that it instead revolved every 34 minutes. This modification allowed for a fitted centre second hand. The spring detent escapement in the present watch had the advantage of showing dead beat half seconds, with the second hand landing on the main division every other beat.