Letter from Derek Price at the Smithsonian Institution, Washington D.C., U.S.A., about a report by a medical man in China to the United States Patent Office in 1851, on the subject of Chinese clocks, and other matters, 1957-04-12, GBR/1928/NRI/SCC2/109/9. The Papers and Possessions of Joseph Needham, GBR/1928/NRI/NRI2. Needham Research Institute. https://archivesearch.lib.cam.ac.uk/repositories/21/archival_objects/334439 Accessed June 29, 2024.