English remarkable and rare pocket chronometer Circa 1844

Gold open face pocket watch by E.J. Dent
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A remarkable and rare English pocket chronometer, circa 1844. This watch was used to determine the longitude of the most western point of Ireland.
Smooth, polished, consular 18-carat gold case. Signed white enamel dial with radial Roman numerals, outer minutes track, subsidiary dial for the seconds, and gold spade hands. Signed full plate movement, chain/fusee, spring detent escapement, large chronometer screw balance, free-sprung, helical hairspring.
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Diameter: 54 mm
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Weight: 160 g
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Signed: E.J. Dent, London
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The determination of the Longitude of the island of Valentia, Ireland in the year 1844 G. B. Airy decided that he would like to estimate this longitude using a variety of pocket chronometers. Some of these chronometers were the property of the Government, but most of them were lent by their owners, Mr C. Sheepshanks, Mr R. Molyneux, Mr Dent, Mr Parkinson & Frodsham and Mr C. Frodsham.
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The Dent Pocket Chronometers Nos. 5876, 6513 and 6514 were used from June to August 1844. The results of these investigations were published in 1846 by G.B. Airy entitled “Determination of the Longitude of Valentia in Ireland by Transmission of Chronometers”. A series of comparisons were made between Greenwich & Liverpool, Kingston & Liverpool, Greenwich & Kingston and Kingston & Valentia.