be understood as portraits (even if models may be identified), the paintings can not be regarded as conversation pieces. The 20th-century art historian Ellis Waterhouse compares these two works to the "genre serieux" of contemporary French drama, as defined by Denis Diderot and Pierre Beaumarchais, a view endorsed by Egerton. An anonymous review from the time called Wright "a very great and uncommon genius in a peculiar way". Provenance, and portraits The Orrery was painted without a commission, probably in the expectation that it would be bought by Washington Shirley, 5th Earl Ferrers, a British Royal Navy officer who had an orrery of his own, and with whom Wright's friend Peter Perez Burdett was staying while in Derbyshire. Figures thought to be portraits of Burdett and Ferrers feature in the painting, Burdett taking notes and Ferrers seated with a youth next to the orrery. Ferrers purchased the painting, which was exhibited in 1766, for £210, but the 6th Earl auctioned it off, and it is now in the Derby Museum and Art Gallery, where it is on permanent display, close to a working replica of a full-sized mechanical Grand Orrery. A biographer of Wright, Benedict Nicolson, argued in 1968 that John Whitehurst was the model for the lecturer, while another commentator points out the figure's resemblance to "a painting of Isaac Newton by Godfrey Kneller". Close observation of the adult faces in the picture reveals that each one demonstrates one or other of the main phases of the Moon – new moon, half moon, gibbous moon and full moon. Jonathan Powers, in The Philosopher Lecturing on the Orrery, claims that 'the Philosopher' was John Arden, a scholar and lecturer best known for teaching the young Mary Wollstonecraft. Notes References Egerton, Judy (1998), National Gallery Catalogues (new series): The British School. catalogue entry pp. 332–343, Waterhouse, Ellis, (4th Edn, 1978) Painting in Britain, 1530–1790. Penguin Books (now Yale History of Art series), Paintings by Joseph Wright of Derby 1766 paintings Science in art Historical scientific instruments Collections of Derby Museum and Art Gallery Paintings of children