Better known to the English-speaking world by the name under which he published most of his works, Jean-Hyacinthe Magellan, João Jacinto de Magalhães was born on November 4, 1722. His work focused primarily on scientific instruments, and is credited with introducing English scientific instruments, and the work of Joseph Priestley (APS member 1785) to the scientific community in France. The João Jacinto de Magalhães Collection consists of eleven letters written by Magalhães in French, and addressed to correspondents in France dealing primarily with the manufacture and distribution of telescopes and optical instrumentation.

Chiefly correspondence with Alexander John Gaspard Marcet on chemistry, with references to Sir Joseph Banks, Jean Francois Berger, Johan Jakob Berzelius, Jean-Baptiste Biot, and others; a few letters to and from John Bostock, Thomas Cooper, John Wilson Croker, Giovanni Fabbroni, and Henry Penneck.