One autograph letter written and signed by political pamphleteer, James Thomson Callender, to bookseller, Matthew Carey, promising to bring in a copy of "the history about which you enquired," and recommending a friend for a position within Carey's firm, "You advertise for a Clerk. There is a very genteel decent young man, for whose moral Character I can pledge myself without fear, who would perhaps suit you and whom I should be happy to introduce to such a valuable friend as experience entitles me to think you. His name is Joseph Calder...You can if agreeable make a trial of him...," dated October 24, 1793.