Walker, William (1791-1867; Scottish), after Pickersgill, Henry William (1782-1875; English)
Sir Roderick Impey Murchison 1851
Mezzotint, 35.9 x 29.2 cm (image), 54,1 x 39.4 cm (sheet)
Presented by Kenneth Robert Murchison, 1894
State Library of Victoria (H5413) 

The sitter (1792-1871), a noted Scottish geologist, first identified the Silurian period (1839). Much of his later life was devoted to the Royal Geographical Society, of which he was a founder member in 1830.

Pickersgill painted numerous portraits of significant British figures of his day; his original oil portrait of Murchison is in the art collection of the University of Edinburgh.

The date of donation of this print to the Melbourne collection is given as 1894 in the NGV’s annual report for that year (and also in NGV 1894 and 1905). The donor was the sitter’s nephew.

Refs.

AR 1894, p.22; NGV 1894, p.127 (V.Buvelot Gallery, south wall, no.3); NGV 1905, p.151 (V.Buvelot Gallery, south wall, no.8) 

See SLV online catalogue entry, with reproduction as shown here, suggesting an accession date of c.1930

Wikipedia provides informative entries on Murchison, the Silurian period, and Pickersgill; for a reproduction of the latter’s oil portrait of Murchison (indicating a date of 1871), see http://images.is.ed.ac.uk/luna/servlet/detail/UoEart~1~1~4564~100420:Sir-Roderick-Impey-Murchison; and for Pickersgill, see also Bénézit 10, pp.1382-83

For Walker, see Bénézit 14, p.582. For Kenneth Robert Murchison (1829-97), see e.g. http://www.thepeerage.com/p70825.htm