Painting, Christian Augustus Augustus Siebe (1788-1874) / by Ernst Augustus Becker (fl. 1840-1859), 1859. Oil on canvas; 126x113cm (sight) in gilt frame 152x129x7cm, signed and inscribed br. Portrait, TQL to R; inventor of 'closed' helmet diving dress in 1840; stands with slide rule in hand, beside scales, diving equipment and helmet.