This image previously appeared in Terry Bennett's "History of Photography in China: Western Photographers 1861–1879", published by Bernard Quaritch in 2010, with the caption:
Fig. 1.18. William P. Floyd. ‘General View of Canton,’ c.1870. Numbered ‘33’ on the photographer’s printed label. Author’s Collection.
See http://gwulo.com/node/35363 for more information.
It is reproduced here with the permission of the author and publisher.