Frederick Fores was a printseller.
Although the name appears to be written 'Fore' in JW's correspondence, it is more likely that it should read 'Fores'. There are several people of the name Fores including Frederick Fores, a printsellerGeorge P. B. Fores, a fine art publisher, and Arthur Fores, of Blucher and Co., printsellers and publishers at 41 Piccadilly. Frederick is the one most likely to have known Whistler, in the late 1870s.
Kelly's Post Office Directory, London, 1860, 1861, and 1862; UK census 1881, from http://www.familysearch.org (accessed 2004).