Rare 2-day box chronometer with electric contacts, probably made for Observatory use, 1916.
Original 2-piece finely figured brass-bound mahogany box, the brass furniture retaining most of the original lacquer. Fullplate fusee movement retaining most of its original spotting, the frame stamped JP (Joseph Preston), with electric contacts and insulating block let into the brass-edge and bowl, with original connecting wires to contacts on the side of the box. Spring-detent escapement of standard late Earnshaw form, with beautiful 'black polished' foot detent. Compensation balance, 11-turn Palladium helical balance-spring. Silvered dial with 24-hr indication and small window in the seconds showing the once per minute electric make/break action, blued-steel hands. Box 15 x 15 x 11 cm tall.
Edward John Dent, one time partner of John Roger Arnold, quickly became one of London's greatest and best known chronometer makers, publishing numerous tracts on the subject as well as designing various compensation balances aimed at overcoming 'mte' - middle temperature error.
Joseph Preston, the most famous of Liverpool watch and chronometer rough movement manufacturers, supplier to all the best English finishers and retailers of his day.
NB: Though often referred to as 'marine chronometers,' the far better and more accurate term is 'box chronometer' as not all were used at sea. Many were instead used for land survey work, mapping and in astronomical Observatories, and others were often used as a portable regulator by households with more than one address, by High Street Jewellers as a 'standard' time source, and diplomats working abroad, etc. One reason the condition of this example is so good and original is that it was never used at sea. Originally rated to sidereal time (+3min 56 secs a day), rather than mean time, I believe this was one of a small number of such chronometers intended for use in Observatories. Vaudrey Mercer in his book Edward John Dent, shows details of the finishing of No 56184, page 693, and his Supplement shows just how few were rated for star (sidereal) time.
The box has not been refinished, just lightly polished, and has no real faults to speak of. Movement and dial both in very good and original condition, the original detent in perfect condition as is the balance. Serviced and guaranteed. NB: This chronometer is in the United Kingdom and will need specialist shipping and handling. Please enquire as to likely costs.
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