Cornelius Cox was a stockbroker and collector. He lived at 8 Leighton Crest, London, with his wife Jane E. Cox. They had seven children: Jane Wells (b. ca 1856), who became a painter; Henry Oscar (b. ca 1858), who became a commercial clerk at a lithographic printers; Ernest F. (b. 1860), who became a commercial clerk at a cartridge makers; and Albert J. (b. ca 1862), who became a commercial clerk for a fire insurance office, and 3 younger daughters. Later he lived at 50 Fellowes Road Hampstead, but died at Croyland, Woburn Sands, Bedfordshire.
Cox was a member of the London Stock Exchange. He bought two albums of documents, letters and paper cuttings about JW from a second hand bookshop for fourteen pounds. Charles Augustus Howell had compiled these albums and Cox purchased them some time after his death. He showed them to his son-in-law, the printer and lithographer Thomas Robert Way, and agreed to exchange them for some sketches of Venice by JW. In a letter written by JW to Howell in 1887, JW declared that he wanted nothing removed from the albums. However, Pennell noted that Cox removed some drawings before he showed the albums to Howell.
Cox's library was sold by Christie's, London, on 10-13 December 1889 and his collection of Wedgwood on 10-13 March 1890.
UK census 1881, from http://www.familysearch.org (accessed 2004); The Times, London, Friday, 7 June 1889, p. 1; Pennell, Elizabeth Robins, and Joseph Pennell, The Life of James McNeill Whistler, 2 vols, London and Philadelphia, 1908.