Diary of John Adams, volume 1
A fair, cold day. Drank Tea at Mrs. Paines. All day, in high health, and spirits. Writing Tillotson. That Comet which appeared in 1682, is expected again this year, and we have intelligence, that it has been seen, about 10 days since, near midnight, in the East.1—I find my self very much inclin’d to an unreasonable absence of mind, and to a morose, unsociable disposition. Let it therefore be my constant endeavour to reform these great faults.
The reference is to Halley’s comet, named for the British astronomer who had worked out the periodicity of its appearance, approximately every three-quarters of a century. Its next return after 1682 was in April–May 1759, so that the reports JA had heard were mistaken. Professor John Winthrop provided an account of Halley’s comet in an appendix to his Two Lectures on Comets, Read in the Chapel of Harvard-College ... in April, 1759, Boston, 1759