Historical Photographs of China reference for this set: Nh18. Medium - Miscellaneous medium-sized photographs 其它中型照片.
The entrance to an underground optical factory,
part of the Central Machine Works (Guo li zhong yang ji qi chang
國立中央機器厰), built into the mountains in a valley near Kunming 昆明, Yunnan
Photographs from the collection may be reproduced only with written permission. For permissions, contact the Librarian, East Asian History of Science Library, Needham Research Institute. Further information about the library and the ‘Joseph Needham Photographs – Wartime China, 1943-1946’: http://www.nri.cam.ac.uk/JN_wartime_photos/home.htm