Cornelius did not make much of his achievement of the first human photograph in the United States. It survived due to the efforts of Marcus Aurelius Root, a pupil at Cornelius' studio. Root published "The Camera and The Pencil" which provided background on the roots of photography in the United States. The book was highlighted at the Centennial Exhibition in Philadelphia in 1876 and caught the attention of Julius Sachse, a noted Philadelphia photographer and future editor of "American Journal of Photography". Sachse began interviewing Cornelius and other members of the American Philosophical Society in order to record the history of photography in the United States correctly. Cornelius told Sachse that he began taking photographs in October 1839 but no evidence was found of his claim until 1975 when a librarian at the American Philosophical Society discovered photographs taken by Cornelius dated in 1839.