An extremely rare and fine mid-19th century brass-bound rosewood two-day marine chronometer with Hartnup balance. Previously with the Time Museum, and more recently exhibited at The Prescot MuseumWilliam B Crisp, London, Number 381The three-part case with missing cartouche to the top lid, the centre section with brass flowerhead button above an ivory signature plaque, Hartnup Balance Willm. B. Crisp London No 381, the lower section with campaign hanldes, inlaid brass escutcheon and blank ivory number plaque. Internally, the case has a full-length hinge, gimbal lock and safety winding key secured in a quadrant. The centre section applied with a label for Thomas Petley, Chronometer, Watchmaker and Nautical Optician, Sydney, New South Wales and D,McGregor & Co., Greenock, Scotland. The 3.75-inch silvered dial signed across the centre Willm. Crisp Maker to the Admiralty 81 St.John Street Rd London No 381 with Arabic minute ring framing the Roman chapters, with gold spade hands, the subsidiary power reserve dial at XII running from 0-56hours in 8 one-hour increments with instruction to wind at 24, the large observatory-style seconds dial between V-VII with blued steel hands. The spotted full plate movement with four ringed pillars and maintaining power to the reverse chain fusee, free sprung blued steel helical balance spring with diamond endstone to an Earnshaw type escapement with Hartnup balance, sitting in a weighted, gimballed bowl. Ticking, together with a Tipsy key. 20cms (7.5ins) highFootnotes:Exhibited 'Your Time', an exhibition by the Northern Section of the Antiquarian Horological Society at Prescot Museum, February-April 2008; Williamson Museum & Art Gallery, Birkenhead February-April 2008. Exhibit P18.According to the exhibition, the movement came from Joseph Preston, who was working out of Prescot. Joseph Preston were well-known watch and chronometer movement manufacturers and their mark 'J.P.' was considered a hallmark of quality. Although based in Prescot, they formed a key link in the national supply chain that saw parts made largely in the North of England, and the West Midlands and assembled into a rough movement, before being sent to London for finishing and sale. A sizeable part of Preston's client base was in London, and to a lesser extent, Coventry.The firm was founded by Joseph Preston in 1829 at 19 Eccleston Street Prescot, and renamed 'Joseph Preston and Sons' in 1840, when his sons Thomas and Joseph began working there full time. In 1891, at the age of 16, the Prestons' nephew, Harry Pybus, began working in the shop. He worked at, and learnt, the twenty separate trades employed in the shop, that resulted in a complete, unfinished watch or chronometer movement. Pybus took over the shop on his uncles' death, though he kept the name 'Joseph Preston and Sons'. During the second world war, it was noted that, having no other employees, Pybus managed to make several two-day chronometer movements entirely on his own, in a shop which lacked electricity. He would run the shop for nearly sixty years, until his death in 1952; anecdotally he was said to be in the middle of cutting watch escape pinions when he died. In his obituary, he was hailed as 'the last of the old Prescot watchmakers'. The shop was demolished shortly after, making Joseph Preston one of the last independent horological manufacturers to shut in Prescot, an area long famed for supplying high-quality movements.The firm supplied a large range of movements to a varied customer base, which included Mercer, Kullberg, and even Patek Phillipe. William crisp was another regular customer. The Hartnup balance was developed by John Hartnup, the first director and founder of the Siderial Liverpool Observatory, established in 1843. The Hartnup balance corrects for middle-temperature error in chronometers. The middle temperature error refers to the error produced in standard compensation balances: The balance is designed to account for an extreme high temperature error and an extreme low temperature error, however, between this range the chronometer gains a bit, and loses a bit when exposed to temperatures outside this range. This means that when a chronometer is exposed to a wide range of temperatures the rate will change much more then when the temperature exposure range is small.Hartnup's solution, likely created around 1847 and actually made by William Shepherd of 13 Bath Street Liverpool, involved laminated cross-bars connecting a fairly standard compensation rim; the outer rim would compensate for extremes and the inner cross-bars would moderate the middle temperature. Hartnup did not patent this balance, partially as he was eager to see it taken up by many makers as an improvement in timekeeping generally, but also because he didn't think that, as a Director of the Observatory, he could profit from work done during his tenure. The balance was never widely adopted, not least because it took twice as long to manufacture as a standard compensation balance did, meaning that chronometers with a Hartnup balance are quite uncommon. Penney, D. (2007) 'Evidence from the Transient', Antiquarian Horology, Vol. 30 (2), pgs. 177-179Aked, C. (1989) 'Joseph Preston and Sons', Antiquarian Horology, Vol. 18 (3), pgs. 298-306Law, R. J. (1990) 'Joseph Preston & Sons', Antiquarian Horology, Vol. 18 (5), pgs. 551-552British Horological Institute (2001) 'Branches: Midlands', Horological Journal, Vol. 143 (8), p. 278Smith, R. W. (1983) 'The Hartnup Balance', Antiquarian Horology, Vol. 14 (1), pgs. 39-45This lot is subject to the following lot symbols: Y ФY Subject to CITES regulations when exporting items outside of the UK, see clause 13.Ф This lot contains or is made of ivory and cannot be imported into the USA or any country within the EU.For further information on this lot please visit Bonhams.com
