Two Lectures on Comets, read in the chapel of Harvard College in Cambridge, New-England, in April 1759. On occasion of the comet which appear'd in that month. With an appendix, concerning the revolutions of the comet, and of some others. Published by the general desire of the hearers.

First edition; tall quarto (20 x 12 cm); contemporary ownership signature to the title and manuscript date to the first leaf of the contents, lacking the half title, some spotting to contents; recent red cloth, title to spine gilt, new endpapers, spine a little faded, front pastedown slightly abraded from bookplate removal, a very good copy; 44 pp and xviii pp appendix. First edition of this uncommon popular work by 'arguably the best scientist in colonial America' (Oxford Dictionary of National Biography). The 1758/59 appearance of Halley's comet was the first predicted by Edmund Halley, who discovered its periodicity, and it was therefore of great interest to both scientists and the general public. Author John Winthrop (1714-1779), a descendant of the founder of the Massachusetts Bay Colony, was elected Hollis professorship of mathematics and natural philosophy at Harvard aged only twenty-three. 'He explored the fields of astronomy, mathematics, and seismology with diligence and flair, publishing eleven articles in the Philosophical Transactions of the Royal Society. His achievements in astronomy, particularly in the study of comets and the relationship between sunspots and the sun's aurora, have been especially celebrated. Winthrop was also a dedicated teacher, explaining the work of other scientists and his own to students and the public at large through lectures, demonstrations, and a host of newspaper and magazine articles' (ODNB).…