This view of the recently completed aqueduct near Caserta, to the north of Naples, was copied from a composition by John Robert Cozens (1752–97) (see figure 1). It was produced at the home of Dr Thomas Monro (1759–1833), where Girtin and his contemporary Joseph Mallord William Turner (1775–1851) were employed across three winters, probably between 1794 and 1797, to make ‘finished drawings’ from the ‘Copies’ of the ‘outlines or unfinished drawings of Cozens’. The majority of the resulting watercolours saw the two artists engaged in a unique collaboration; as they later recalled, Girtin ‘drew in outlines and Turner washed in the effects’. ‘They went at 6 and staid till Ten’, which may account for the generally monochrome appearance of the works, and, as the diarist Joseph Farington (1747–1821) reported, Turner received ‘3s. 6d each night’, though ‘Girtin did not say what He had’ (Farington, Diary, 12 November 1798).¹

Cozens’ on-the-spot sketch is inscribed ‘Aqueduct 5 miles beyond Caserta – Novr.26’ (Bell and Girtin, 1935, no.326). The sketch is found in the fifth of the seven sketchbooks from Cozens’ second Italian trip, which saw him travel to Naples in 1782 in the company of his patron William Beckford (1760–1844). It is unlikely that the Monro School watercolour was copied directly from the sketch by Cozens, however. It would have been uncharacteristic of Beckford to have lent the sketchbooks to Monro, and the existence of a large number of tracings of their contents by Cozens himself suggests that the patron, rather than the artist, retained the books. An album put together by Sir George Beaumont (1753–1827), now in the collection of the Yale Center for British Art, New Haven, includes more than seventy tracings from on-the-spot drawings in the first three of the sketchbooks, and these provided the basis for at least thirty Monro School works. There are only five tracings from the next three books, but there is no reason to think that others did not exist, and it was presumably from these lost copies by Cozens that as many as thirty-five more watercolours were produced by Girtin and Turner, including this view of the aqueduct designed by Luigi Vanvitelli (1700–1773). The fact that the Monro School copies never follow either the shading or the distribution of light seen in the on-the-spot sketches, though they always replicate the basic outlines, further suggests that Girtin and Turner worked from tracings of the sketchbook views. The aqueduct was built in the middle of the eighteenth century to supply the area of Caserta with water, and it was consciously modelled on ancient structures, with the result that writers have sometimes mistaken its date.

The bulk of the works sold at Monro’s posthumous sale in 1833 were attributed to Turner alone, but, despite the pioneering article published by Andrew Wilton in 1984, which established the joint authorship of many of the Monro School copies, this work has always been associated solely with Turner (Wilton, 1984a, pp.8–23). Though the issue is not entirely clear, there is nothing to suggest that it is anything other than a typical collaborative effort between Turner and Girtin.