Tracts, Physical and Mathematical. Containing, An Explication of Several Important Points in Physical Astronomy; and, a New Method of ascertaining the Sun's Distance from the Earth, by the Theory of Gravity

Edinburgh: millar, 1761. hardcover. very good. 19 folding engraved plates. vii, [1], 411 pages with rubricated edges. 8vo, full contemporary mottled calf with heavily gilt spine, outer joints with old repairs but still pulling away in spots, early ownership name on title page, off-setting from text onto part of the plates, light scattered foxing. Edinburgh: A. Millar & J. Nourse, 1761. First Edition. Scarce. "In 1761, pursuing his plan of introducing the simplicity of ancient geometrical demonstrations into astronomic investigations, he published Tracts, (truncated) Physical and Mathematical, Containing an Explication of Several Points in Physical Astronomy, in which he developed a treatment of centripetal forces in a series of propositions requiring only a knowledge of the elements of plane geometry and of conic sections. He even tried to deal (employing geometrical methods similar to those of Newton's Principia mathematica) with the difficult 'three body problem' (the study of the trajectories of three masses in mutual gravitational interaction) that had defeated many eighteenth-century mathematicians."-ODNB. (Inventory #: 307482)