Text from Ian Jenkins & Kim Sloan, 'Vases and Volcanoes', BM 1996, cat.180:

Rosa based his image of the philosopher Democritus on Castiglione's etching 'Melancholia', and surrounded him with Classical sculpture, symbolising former glory, and with dried bones, indicating the end of all aspirations. The inscription translates as 'Democritus the mocker of all things is here stopped by the ending of all things' (Kitson, no. 98). The painting on which this etching is based was executed in 1650 and exhibited in the Pantheon in Rome the following year. A companion, 'Diogenes Throwing away his Bowl', was painted and both were purchased by the Venetian ambassador Sagredo (both now Statens Museum for Kunst, Copenhagen). The paintings were in Bouchier Cleeve's collection at Foots Cray Place, Kent, from at least 1761 and were moved by his son-in-law, Sir George Young, to his house in London in 1772. They were included in at least two guides to collections around London, and William Gilpin singled them out for special praise in his 'Southern Tour' (pp.122-3) (Nicolson, 1, pp.52-3). Sir William Hamilton included a painting by Rosa of 'A Philosopher Meditating on the Effect of Time' in his manuscript list of paintings at the Palazzo Sessa, although James Clark did not recognise the subject and described it as 'A Magician with various Impliments of Sorcery' in his packing list. Hamilton provided more information for his sale, indicating that he knew the correct title and that the subject had been etched by Rosa; he also noted there was a larger version in the collection of Sir George Young. He stated that his painting had come from the 'celebrated Collection of the Duke of Laurenzano, for whose collection he had painted it' (Christie's, 27 March 1801, lot 57, bought for £65 by the Earl of Breadalbane). Hamilton could not have been mistaken about where he had purchased the painting, but what he may not have known was that the collection formed by the Dukes of Laurenzano in Rome in the seventeenth century had been added to substantially by two later members of the family who had brought the collection to Naples. The painting is listed in the Laurenzano inventories for 1710 and 1741, where it is described as a philosopher in a wood, but it does not appear in the earlier seventeenth-century inventories (Getty Provenance Index, inv. 1741/11/07). Hamilton's smaller version of the painting was purchased by the Earl of Warwick at the Breadalbane sale on 1 June 1801. It is now on loan to the Metropolitan Museum in New York, but, on the basis of the style of painting and the colours used, it is not considered to be the work of Rosa himself and is thought to be an early copy. Hamilton was quite aware that it was not unknown for Italian owners consciously to sell copies as originals, but in this case, the owner’s family believed it was a work painted for their ancestor. There was no reason for him to doubt that he owned a smaller but autograph version of a famous painting in London. In eighteenth-century Britain, Salvator Rosa was considered to be the finest exponent of the sublime, and the pair of paintings of philosophers which belonged to Sir George Young were among Rosa's largest, most ambitious pictures. The 'Democritus' was acknowledged to be iconographically complex. Rosa's etchings were also widely known, greatly admired and carefully studied throughout the century. Solitary hermits in landscapes and the theme of melancholy contemplation interested British writers and artists searching for new ways to interpret the sublime. Several of them painted variations on the theme, most significantly Joseph Wright of Derby in his 'Philosopher by Lamp Light' of 1769, later known as 'Democritus Studying Anatomy', engraved as a mezzotint by Pether in 1770 (see Egerton, nos 41, 176).