Jean-Paul GRANDJEAN DE FOUCHY (1707–1788), astronomer. Autograph letter, “JP Grandjean the Elder and the Younger,” Paris, February 28, 1724, to Daniel Jousse in Orléans; 3 pages, in-4 format, addressed with a red wax seal bearing the coat of arms (broken). A fine letter from his early years. He humorously complains about his friend’s silence with an amusing quatrain: “That wretched glutton Joussus”…; he thinks his friend is mad and hopes that “the holy season of Lent will bring you to your senses.” He has purchased “a book consisting of two treatises on arithmetic—one by Gemma Frison and the other by Ramus—with notes on the former and a summary of astronomical fractions, along with the method for determining the positions of the sun and moon from memory. […] “If you had been sensible, you would have had the calculation for the lunar eclipse on November 1st, but that will have to wait until you’ve come to your senses.” He can send him “a draft of a new work on gnomonics, in which I reduce all sundials to the horizontal plane. “My treatise on instruments is coming along; the most difficult parts—namely, the quarter-circle and the estuy—are nearly finished,” as well as “the method for drawing an exact meridian line and constructing a gnomon suitable for observing the meridian altitude of the sun in the manner of Mr. De Lisle.” He has “a bundle of curious problems” to submit to him. He concludes with domestic news about his cat, who is pregnant, and provides the longitude and latitude of his location. Attached is a handwritten fragment concerning “reflecting telescopes.”