Livingstone, David, 1813-1873. Letter to George Back, 13 December 1856. Images copyright Royal Geographical Society (with IBG). Used by permission for academic purposes only. For non-academic use permission, please contact the Picture Library. As relevant, copyright Dr. Neil Imray Livingstone Wilson. Creative Commons Attribution-NonCommercial 3.0 Unported (https://creativecommons.org/licenses/by-nc/3.0/). 