William Alexander Chapman was a pawnbroker.
William Alexander Chapman appears to have owned a chain of pawnshops, and Whistler may have been a client during the run-up to his bankruptcy in 1879. Chapman is recorded in the post office directories from the early 1860s, for instance as a pawnbroker at 71 Kensington High Street, Notting Hill; at 33 Kensington High Street and 1 Queen's Row, Pimlico; a dealer in antique china, paintings and first class furniture at 35 Kensington High Street and 1 Queen's Row, Pimlico SW; and a pawnbroker at 1 Queen's Row, Pimlico, in 1863.
W. Chapman is recorded (if it is the same Chapman) as having a Fine art gallery at 47 Buckingham Palace Road in 1881; and as a pawnbroker at the same address, 47 Buckingham Palace Road in 1885; as a Pawnbroker at 46 and 67 Buckingham Palace Road in 1886/1887; again as a Pawnbroker at 67 Buckingham Palace Road in 1887.
Furthermore W. A. Chapman, pawnbroker, is recorded at 47 and 67 Buckingham Palace Road in 1887/1888 Did he have a chain of pawnshops?
Simpson's Chelsea etc Guide, London, 1863; The Chelsea Pimlico and Belgravia Directory for 1881, London, 1881; ibid., 1885; ibid., 1886/1887; Kelly's Directory of Chelsea, Pimlico and Belgravia, 'Buff Book', London, 1887; The Mayfair etc Directory, London 1886-1887 and 1887-1888.