Menelai Sphaericorum Libri III. Quos olim, collatis MSS. Hebraeis & Arabicis, Typis exprimendos curavit Vir Cl. Ed. Halleius L.L.D. R.S.S. & Geometriae Professor Savil. Oxoniensis. [Menelaus’ Spherics].

HALLEY, Edmond. [Benjamin Franklin].

Item Number: 130904

Oxonii [Oxford]: Sumptibus Academicis, 1758.

Exceptionally rare Benjamin Franklin presentation copy of Halley’s edition of Menelaus’s Spherics. Octavo, bound in full contemporary calf with gilt ruling to the spine in six compartments within raised gilt bands, red morocco spine label lettered in gilt. Presentation copy, presented by Benjamin Franklin to Scottish mathematician Robert Simson with Simson’s inscription to the second free endpaper noting that the book was presented to him by Franklin, “Ex dono viri praestantissimi et mihi amicissimi Benjamin Franklin 12mo Martii A.D. 1760, Robert Simson.” Franklin toured Scotland in 1759, the precise year that Halley’s Comet reappeared as predicted, leading French astronomer Nicolas-Louis de Lacaille to name it in his honor. While there, Franklin was granted a doctorate by the University of St. Andrews together with the freedom of the city of Edinburgh and met with the luminaries of the Scottish Enlightenment, including David Hume, Adam Smith, and Robert Simson. He later recalled the tour as ‘six weeks of the densest happiness I have known’ (Fay, Adam Smith and the Scotland of his Day, 1956, p. 124). Simson was a professor of mathematics at Glasgow, renowned for his works on ancient geometry. Adam Smith, who was his student while at university, revered Simson and deemed him one of “the two greatest mathematicians… that have lived in my time” (Theory of Moral Sentiments, 1790 ed, p 312). Upon his return to London in 1760, Franklin gifted Simson this copy of Menelaus’s Spherics, a work foundational to spherical geometry with early astronomical implications, such as determining the trajectory of planets. Importantly, as well, it was Halley himself who suggested to Simson that he specialize in restoring the ancient geometers when they had first met in 1711. As two men of science, Franklin and Simson almost certainly discussed the astronomical news of the day – the 1759 reappearance of Halley’s Comet and the upcoming 1761 transit of Venus; in fact, Simson wrote to another colleague in July 1761 inquiring after details of the astronomical observations that “Dr Bradley, Dr Bevis, Mr short or other good observers have made of the transit of Venus”. With extensive annotations in Simson’s hand including an erratum to title-page verso, marginalia to pages vii, viii, 6, 17 and 18, and four full pages of annotations to rear blank, free endpaper and pastedown. In very good condition. Rebacked. Housed in a custom clamshell box. An exceptionally rare edition of this important work linking three leaders of the Enlightenment and reflecting the collaborative scientific spirit that enabled 18th-century scientists to determine the astronomical unit and take the true measure of the universe.

At the turn of the 18th century, astronomers knew in large part the shape of our solar system, but the precise size of its distances remained uncertain. In 1716, English astronomer Edmond Halley proposed a worldwide experiment to use the 1761 and 1769 Transits of Venus to measure the distance of the earth from the sun (today called the "astronomical unit"), unlocking the size and measure of the solar system. Ever a champion of scientific collaboration, it was Franklin who spurred on America's participation in the 1769 transit experiment which would soon thrust American science into the international limelight. After spearheading American involvement in the experiment, Franklin disseminated the findings of the American scientists, making certain that the American Philosophical Society published the Transit of Venus reports; he himself contributed an article for the Journal of the Royal Society.