A rare George III mahogany hodometer or waywiser Cary, London, Late 18th century With 31.5 inch diameter wheel bound with an iron tyre and with six tapered spokes around a brass hub engaging with take-off gearing contained within the left hand fork of the handle assembly, the right hand fork incorporating a hinged section to allow removal of the wheel with locking via a knurled brass screw, the upper section with inverted 7.25 inch circular silvered register engraved Cary, London to centre within concentric inner scale calibrated in Roman numeral MILES (I to X) and Arabic Furlongs (0 to 8 for each mile) to be read by the shorter of the two blued steel hands within outer scales calibrated in Poles (0 to 40) and Yards (0 to 220) to be read by the longer hand, set behind a hinged glazed circular moulded wooden bezel beneath elaborate yoke-shaped handle 137cm (54ins) high overall. The celebrated Cary family business of scientific instrument and globe makers was established by John Cary at Johnson's Court, Fleet Street, London in 1782 moving to a new address at 'Corner of Arundel Square', Strand the following year. He was primarily an engraver of maps, charts and globes who moved again in 1783 to 188 Strand. By 1791 he had entered into what appeared to be a relatively casual partnership with his brother, William (who was born circa 1759 and apprenticed to Jesse Ramsden); this partnership lasted until circa 1816 by which time William and John Cary had moved again to 181 Strand before finally settling in 86 St. James in 1820. The following year John Cary was succeeded by his sons, John (II) and George Cary, who continued from the firm's 181 Strand address until 1851/2 when the business was acquired by Henry Gould. The current lot would have been a particularly valuable instrument for surveyors charged with creating maps and plans during the latter years of the 18th century. The importance of the instrument's role is reflected in the quality of its construction with the dial in particular being finely engraved and finished. When reviewing comparable surviving instruments of this type it becomes clear that different makers such as Dollond, Thomas Rubergall, William Frazer, and W. and S. Jones appear to have sold essentially identical instruments. This would suggest that they were probably made in one workshop who then supplied them to various makers for retail. One possible candidate for the supplier would be the workshop George Adams, as several earlier variants of this design by him are known including an example in the King George III collection housed at The Science Museum, London. This suggests that Adams was used to making such instruments hence was best suited to supply them in reasonable numbers to other makers.