Surveyor's compass used by James Watt

Surveyor's compass used by James Watt, by George Adams, London, circa 1760.

A pivotal part of the engineer James Watt’s early career was spent as a surveyor, working on projects as the Monkland Canal supplying Glasgow. His workshop (inv 1924-792) contains a number of artefacts from Watt’s surveying projects, including a tripod, but not a compass, which would have been an essential part of his professional kit. This is that object. It is made by the pre-eminent London maker of such instruments, making it a significant investment by the young Watt, and reflecting the importance of surveying in underpinning his future career.

The object is most likely by George Adams the elder (c1709-1773). It is signed on the lid 'made by G.ADAMS in Fleet Street Inst. Maker to His Royal Highness the PRINCE OF WALES'. The silvered compass rose is engraved with eight cardinal points and a double degree scale, in a brass drum case mounted with four external open sights, two housed in the lid and two more in the base. It has a socket/thumbscrew to fit on top of a tripod (which is in Watt’s workshop, inv. 1924-792/1904) – checks show an intimate fit between the two, down to the positioning of the hole made by the thumbscrew in the tripod head.