James Clark Maxwell and his wife by Jemima Blackburn, Jemima Blackburn, before 1879

James clerk maxwell (1831–1879), cavendish professor (1871–1879), and his wife, katherine mary clerk maxwell, née dewar (1824–1886), attributed to jemima blackburn (1823-1909), in cavendish laboratory, university of cambridge. Date: before 1879.