An Account of the Equatorial Instrument

London: Phil. Trans., [1793]. OFFPRINT.. Original blue paper wrappers.. Very good; some occasional spotting; front upper fore corner of wrapper reinforced; backstrip worn; wrappers chipped at the extremities; ownership stamp on the title.. 4to, [2], [3] - 64 pp + 3 folding tables and 6 large folding plates.

The original offprint illustrating and explaining the design of the great Ramsden equatorial. The instrument and work described herein was the culmination of a life's work and experience. Commencing with the publication of his Description of (truncated) a New Universal Equatorial Instrument in 1774 Ramsden embarked upon an unprecedented career. He was elected a Fellow of the Royal Society in 1786 and winner of the Copley Medal ( for, '... various inventions and improvements in philosophical instruments.' ) in 1795. The quadrant described herein was constructed for George Shuckburgh's private observatory. The description of the device is lengthy (over 60 pages) and is accompanied by generous fold-out illustrations. Ramsden's workshop completed the commission to the delight of Shuckburgh who wrote: ' ... I am entitled to believe that the accuracy of these divisions under consideration is hardly to be equalled, and still less to be excelled, by that of any astronomical instrument in Europe ....' Schuckburgh presented this copy to a contemporary member of the Royal Society, Charles Englefield, scientist and mathematician. Daumas illustrates the instrument (plate 96) in his discussion Ramsden and astronomical instrumentation. Daumas, p. 170; King, Telescope, p. 171; DSB II, 284 -`5; Bennett, Divided Circle; see McConnell's book on Ramsden. (Inventory #: 10014)