London, England; ca. 1750; mahogany case, brass works; 198.1 x 41 x 23.5 cm. CMC D-5579

Samuel Johannes Holland, in 1764 appointed the first surveyor general of British North America, cherished the precise astronomical clock that would make his maps valuable references for many years. The clock's maker was George Graham, renowned British designer of precision instruments.

Holland used the clock to determine the longitudes for surveys of Prince Edward Island, Cape Breton, the lower St. Lawrence valley, the coast of New England, and areas of Upper and Lower Canada. His astronomical observations were published by the Royal Society. Holland set high standards of accuracy in land measurement and mapping, made important contributions to astronomy and geography, and trained many young surveyors and cartographers.