Pierre-Samuel DU PONT DE NEMOURS (1739–1817). Autograph letter, February 21, 1809, to Dr. Antoine PORTAL; 2 pages, in-4 format, with address. On copyright, regarding Antoine Portal’s (1742–1832) book *Observations on the Nature and Treatment of Pulmonary Tuberculosis* (du Pont, 1792): “I produced the first edition of it when I was a printer; and I did so out of friendship for you, out of esteem for your intellect. But you had not sold me the copyright to the book, so I could not transfer it, and I did not transfer it to anyone since I did not own it. I do not take what belongs to others. My rights to the edition that came off my presses are limited to the copies it produced.” He does not know whether a copy was deposited at the National Library: “If this was overlooked, you still have time to deposit two copies of the second edition there. No bookseller may reprint this work during your lifetime without your permission; and when you are no longer here, no one may do so without your family’s consent until ten years after your death. That is the current law. Perhaps in the future, ownership of works will be extended to the authors’ families, just as with other property. Had this been considered, it is certain that the descendants of Corneille, Racine, and La Fontaine would not have needed assistance from the government. This kind of reward would always be precisely proportionate to merit"... [A second edition of Portal’s book was published in 1809 by L. Collin.]