Two portraits by this artist, those of Mr Thomas Richards, Penzance Hairdresser (1856) and Mrs Thomas Richards, his Wife (1856) are in the possession of Penlee House Museum. At the RCM, Truro is his portrait of Tamson Blight (1798-1856), the White Witch of Helston painted in the year of her death 1856. Chapman's portrait of John Ferris Bennallack, mayor from 1819 to 1823, is in the collection of Truro City Council.

A recent correspondent writes (2013): We have in the family a portrait painted by Wm J Chapman in 1857, of my great-grandfather Benjamin Bosence of Alverton, where he had a business as fellmonger and, later bootmaker and tanner.