An English architect and editor, Knowles may have known JW in the mid-seventies, when his name appears in an address book (#12714).
He founded the Nineteenth Century in 1877, having prior to that date edited the Contemporary Review. He was a friend of Tennyson, for whom he designed a house.
Kelly's London Postal Directory, London; Lugt, Frits, Les marques de collections de dessins et d'estampes: marques estampillèes et écrites de collections particulières et publiques; marques de marchands, de monteurs et d'imprimeurs; etc..., Amsterdam, 1921, no. 1546; Dictionary of National Biography, Oxford, 2004.