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.

Kendall, Larcum (1719-90) was born on 21 September 1719 at Charlbury in Oxfordshire, the elder of two children of Moses Kendall, Mercer and Linen Draper, and Anne Larcum (originally of Chipping Wiccombe, Bucks) who married on 18 June 1718. His parents were both Quakers and he had one brother, Moses. On 7 April 1735 Larcum was apprenticed to the watch, clock and repeating-motion maker John Jefferys for seven years, at which time he was living with his parents in St Clement Danes in Westminster, London. In 1736 his maternal grandfather (Nicholas Larcum, a salesman of Chipping Wycombe) left property in trust for him, through his mother, and he inherited a reasonable private income (in his will he left 3% annuities on a capital of £1,200, to his brother Moses and thence to Moses's children).

In 1742, immediately after his apprenticeship had ended, he set up on his own, working almost exclusively for the great watch and clockmaker George Graham (1685-1751), as an escapement maker specialising in the horizontal (cylinder) escapement. He was brought up a Quaker, but once his own master he no longer stayed as one of their brethren; though, according to his obituary he ‘never quitted that simplicity of manners for which that sect is so generally admired; and a man more inflexibly upright, either in person, word or deed, perhaps scarcely ever lived’. He was highly respected as a craftsman too; working under Graham and with his contemporary Thomas Mudge, he was part of the finest watch making team of the day. He appears though to have remained something of a loner in the trade; he was not a member of the Clockmakers' Company and doesn't seem to have been part of the group of talented London (ex-City) watchmakers who met at the Devil Tavern during the last quarter of the 18th century. However, through Jefferys and Graham, Kendall had connections with John Harrison, the great pioneer and inventor of the marine timekeeper and precision watch.

In June 1765, by which time he was established at No.6 Furnival's Inn Court, near Holborn Barrs, the Board of Longitude selected him as one of six experts to witness the explanation by Harrison of the construction of his fourth timekeeper, an event which took place between 14 and 22 August that year. During these deliberations the Board also decided that a copy of the timekeeper must be made and Harrison recommended Kendall, who may have contributed to the making of the fourth timekeeper itself in the preceding years. Kendall agreed to make the copy 'part for part', but made it clear he had little faith in its design; he would make no guarantees of its good performance. The copy (now known as 'K1') was completed in 1769 and the following year was inspected by the same group as before, including Harrison's son William, who admitted that it was even better made than his father's original. Kendall was paid the agreed £450, plus an ex-gratia payment of £50 for ‘...the extraordinary trouble in adjusting it for 9 months’ and taking it and H4 to pieces.

In 1772 K1 was sent for trials with James Cook on his second voyage of discovery to the South Seas (1772-75), during which time it performed so well Cook learned to rely on his ‘trusty friend the watch’, his ‘never failing guide’. Nevertheless, Harrison's design was too complex and expensive and in 1769 the Board commissioned Kendall to create a simplified version. The result, 'K2' of 1771 (at £200) was later famous for being on HM ship ‘Bounty’ when the infamous mutiny took place. The watch was taken to Pitcairn Island, only returning to England in 1840. It employed many of the features of H4, but Kendall omitted the essential remontoir mechanism, thus prejudicing its chances of success and it never performed well. Further simplified designs by Kendall, including a type of escapement said to be his own invention, resulted in 'K3' of 1774 (at £100) which was sent with Cook on his third ill-fated voyage (1776-79). This watch also failed to perform as well as Harrison's, being fundamentally no better than K2 (These three timekeepers are all preserved at the National Maritime Museum, Greenwich).

After this Kendall, following the lead of the great pioneer John Arnold, began making pocket timekeepers with 'detached' (pivoted detent) escapements (an example is in the collection of the Worshipful Company of Clockmakers, Guildhall, London). The quality of his work was second to none, as is shown by the few watches, signed by him, which remain today, but he never showed any real ingenuity of his own. He was primarily a watchmaker to the top retail trade, producing first rate products to the design of those with greater imagination; the majority of his work, which also included some clocks and precision regulators, would appear to have been sold under other retailer's names.

He died at Furnival's Inn Court on 22 November 1790. His obituary states that the Quakers ‘...received his body into the bosom of their church at his death...’ and he was buried in the Quaker cemetery at Kingston in Surrey on 28 November 1790. As well as leaving a large sum in trust for his brother and family, his will, written on 6 November 1790 and proved on 8 December, also leaves his 'implements in trade', personal effects etc., to Moses, who evidently then arranged for them to be sold by auction; the contents of his workshop, and his household furniture and other effects were sold by Christies on 23 December that year. It is not known whether Kendall ever married. No wife or children are mentioned in his will and the furniture and effects sold strongly suggest the home of a lifelong bachelor.