This slight sketch, as well as other related drawings on folios 53 verso and 54 verso (D15659 and D15661; Turner Bequest CLXXXIV 51a and 52a), represent Turner’s impressions of his experience walking through the Grotto of Posillipo (known today as the Crypta Neapolitana), a Roman tunnel through the Posillipo Hill which was built during the first century BC in order to link Naples with Pozzuoli to the west. An impressive feat of ancient engineering, legend had it that the tunnel been magically created by the classical poet, Virgil, whose villa was said to be nearby. Nearly half a mile in length, it was both an important thoroughfare and a popular tourist attraction, and represented an established motif for British artists visiting the city.1
The darkness inside the tunnel would have made on-the-spot sketching difficult, although a dim light was admitted into the interior by two apertures bored through the rock. The forms and outlines within the artist’s swift pencil study are disorientated and overlapping, suggesting that he was unable to see what he was doing. Nevertheless, the rough lines capture a sense of the impressive height of the cavernous passageway and the craggy walls and ceiling. The scene includes a number of travellers passing through the tunnel, some on foot and others mounted. A more detailed and conventional view of the entrance to the Grotto can be seen in the Naples, Rome C. Studies sketchbook (Tate D16098; Turner Bequest CLXXXVII 11).
Images of the tunnel include, for example, Thomas Jones (1742–1803), The Grotto of Posillipo, oil on paper, 1782 (Gere Collection), William Pars (1742–82), The Grotto at Posillipo (Birmingham City Museum and Art Gallery) and Francis Towne (1740–1816), The Grotto at Posillipo, watercolour, 1781 (British Museum), all reproduced in colour in Anna Ottani Cavina, Un Paese Incantato: Italia Dipinta da Thomas Jones a Corot, exhibition catalogue, Galeries nationales du Grand Palais, Parigi and Palazzo Te, Mantova, Italy 2001, nos.38–40, pp.60–3, and Francis W. Hawcroft, Travels in Italy 1776–1783: Based on the ‘Memoirs’ of Thomas Jones, exhibition catalogue, Whitworth Art Gallery, Manchester 1988, nos.132–5, pp.111 and 116. See also John ‘Warwick’ Smith (1749–1831), Grotto of Pausilippo 1778–9, watercolour (Tate, T08492), and drawings by James Hakewill (1778–1843), reproduced in Tony Cubberley and Luke Herrmann, Twilight of the Grand Tour: A catalogue of the drawings by James Hakewill in the British School at Rome Library, Rome 1992, nos.5.51–2, pp.281–3.