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 by STEWART, Matthew

19 folding engraved plates. vii, [1], 411 pp. Thick 8vo, a fine Scottish "herringbone" binding of cont. dark green morocco (foot of upper joint with one small & careful repair), sides richly gilt in a "herringbone" design, spine richly gilt, red morocco lettering piece on spine, a.e.g. Edinburgh: A. Millar & J. Nourse, 1761. First edition, thick paper copy, bound in dark green morocco with a most handsome contemporary Scottish "herringbone" design. Stewart (1717-85), was the successor to Colin Maclaurin in the chair of mathematics at Edinburgh and established his reputation as a mathematician by the publication of his General Theorems (1746). Michel Chasles considers Stewart and Robert Simson amongst the most important contributors to the progress of geometry. "In 1761, pursuing his plan of introducing the simplicity of ancient geometrical demonstrations into astronomic investigations, he published Tracts, 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. "After his election to the chair [in 1746], Stewart's interests turned to astronomy and natural philosophy; and he displayed great ingenuity in devising purely geometrical proofs of results in these subjects that had previously been established by the use of algebraic and analytical methods. Examples of this kind are to be seen in [the present book]."-D.S.B., XIII, p. 54. Fine copy.