found: [Cartes de visite of artists], [between 1860 and 1890](John Watkins, photographer, London)
found: Wikipedia, November 16, 2015(John Watkins, 1823-1874, English portrait photographer; he and his brother, Octavius Charles Watkins, often worked together; they made studio portraits of artists and other culturally influential people between 1840 and 1875)
found: Charles Dickens seated, on Museum of London website, viewed November 16, 2015(John and Charles Watkins had a studio at 34 Parliament Street, Westminster; the studio operated under John Watkins from 1851-1865, then was succeeded by Watkins Bros.; John Watkins died in 1874)
found: African explorers, ca. 1868-1870s:verso stamps (John Watkins, photographer to the queen, London SW; John Watkins, Parliament)
found: British National Port. Gallery website, Jan. 12, 2007(John Watkins (floruit late 1840s-1875))
found: International guide to nineteenth-century photographers and their works, 1988:p. 559 (Watkins, John and/or Charles (British), photos dated 1860s)