Sir Jonas Moore (1617-79) - practical mathematician, teacher, author, surveyor, cartographer, Ordnance Officer, courtier and patron of astronomy -had a remarkable career, and was one of the first to make a substantial fortune frommathematical practice. Dr Willmoth follows his progress to a knighthood, membership of the Royal Society, and favour at the court of Charles II; she assesses his contribution to the draining of the Great Level (under Cornelius Vermuyden) and the building of the Mole at Tangier, and records how, as Surveyor-General of the Ordnance, he became a patron of the new Royal Observatory at Greenwich. Her researches illustrate the changing views of mathematics at the time, and reinforce the argument for the 17th-century `scientific revolution'.FRANCES WILLMOTH is currently working on an edition of John Flamsteed's correspondence. [East Anglian] Study of the life and varied career of SirJonas Moore (1617-79) - practical mathematician, teacher, author, surveyor, cartographer, Ordnance Officer, courtier and patron of astronomy - who was involved in the draining of the Great Level in the Fens.