Experimental watch movement with two balance wheels, by John Grant, London, 1800. White enamel dial with gold coloured hands. Fusee movement with lever escapement, the balance staff of which has a cranked roller, and the escape wheel raised teeth. There are two balance wheels, each of which carries a wheel with 80 teeth. These wheels gear together, causing the action of the two balances to be similar but in contrary directions. Signed ‘J.G. London May 1800’. Presented in 1850 to the Worshipful Company of Clockmakers, by the maker's son, John Grant Jnr. Clockmakers' Museum No. 460