Marine timekeeper 'K1'

A one day marine timekeeper with a 102mm diameter white enamel dial, in imitation of that of H4, with scrolling decoration at the quarters and roman hour numerals and Arabic ten-minute figures. It has polished and blued steel beetle and poker hands with a fine polished steel pointer seconds hand with a counter poised tail.The timekeeper has a brass, one-day full plate fusee movement with four turned pillars, with a highly engraved slide plate, balance bridge and third wheel bridge. The plate is engraved 'Larcum Kendall LONDON 1769'. The general level of finish of the brass-work is very high with all brass movement parts highly polished. The fusee, which has Harrison's maintaining power, has a brass pipe around the winding square. The timekeeper has a nominal four-wheel train plus a great wheel with a remontoir interposed at the fourth wheel. The third wheel, with internally cut teeth, runs within the potence plate and meshes with a fourth (remontoir) wheel, leading to a fifth and fly, with the remontoir spring driving a fourth (contrate) wheel, which drives the steel escape wheel.The timekeeper contains Harrison's adapted verge escapement with diamond pallets, acting with the hardened steel escape wheel (correctly called the 'balance wheel'). The hardened steel balance has a three turn blued steel spiral balance spring, of tapered form, with a long, somewhat straighter tail, acting against a bimetallic compensation curb, and a secondary 'isochronal curb pin. The jewelling extends to the balance (diamond upper endstone in a polished steel setting), escape wheel, contrate wheel and third wheel, all with endstones, and the pallets as mentioned.The timekeeper is held in a large, silver pair case with stirrup bow, 165mms high, 124mms wide and 28mms deep. Both inner and outer cases are hallmarked for London, 1769-70 and with the case-maker's mark 'P.M'. for Peter Mournier of Frith St, Soho.The chronometer is in fine, original condition. The case has a few slight scratches to the finish, and was rhodium plated in the 1940s. The dial enamel is perfect and the movement is in excellent clean, working condition.The timekeeper was commissioned by the Board of Longitude as a copy of H4 in 1766 and was completed in 1769. It was issued to Captain James Cook on his second and third great voyages of discovery to the South Seas, after which it went with Captain Arthur Phillip and the 'First Fleet' to found the first colony in Australia. It was then passed to Vice Admiral Sir John Jervis in HMS 'Victory', and returned to the Board in 1802. It was placed on permanent loan to the NMM in 1937.Larcum Kendall