Lot 64
Bradley, James (1693-1762)
Autograph letter signed to James Stirling
The Library of James Stirling, Mathematician
Auction: 23 October 2025 from 13:00 GMT
Description
dated Oxford, 2nd December 1733, regarding ‘The Figure of the Earth’ and ‘The Jamaican Experiment’: 'I apprehend this Retardation of the Clock (so much greater than what is derived by a Computation founded on the Principles of Gravity and an Uniform Density in ye several parts of the Earth) must be rather ascribed to an inequality in the Density of the parts of ye Earth near which the Clock is fix'd, than to the greater Heat. For the greatest part of the force of Gravity upon any particular Body arising from the parts of the Earth that are near it …', 3pp., 18.5 x 22.5cm, a little tear to signature with slight loss
Footnote
Stirling's contemporary at Balliol College, Oxford, John Bradley was appointed fellow of the Royal Society in 1718, Oxford professor of astronomy in 1721, and astronomer royal in 1742 on the death of Edmond Halley. His principal discovery is the aberration of starlight, ‘the first direct evidence for the revolution of the Earth around the Sun’ (Ency. Brit.). Stirling's 1735 paper, 'Of the Figure of the Earth, and the Variation of Gravity on the Surface', has been identified as 'an important contribution to the theoretical study of the earth's shape and its gravitational forces' (ODNB). He was overtaken in his work on the subject by Colin Maclaurin and others, though it is clear from his surviving letters that he would have made a more substantial contribution but for his commitments as manager of the mines at Leadhills.
Published:
Charles Tweedie, James Stirling: a Sketch of his Life and Works along with his Scientific Correspondence, 1922, pp. 161-2.