In this passage, added in the third edition, Ruskin first writes of the great group of Swiss watercolours executed by Turner in 1842 and 1843 ( Wilton 1523-1539). In Praeterita, he recalled that the artist 'wanted to make some drawings to please himself; but also to be paid for making them,' and on Turner's behalf the dealer Thomas Griffith sought commissions, at eighty guineas per subject, from the most avid collectors of his work, B.G. Windus, Elhanan Bicknell, Hugh Munro of Novar, and Ruskin and John James Ruskin.
Based on the sight of fifteen sketches and four 'specimens' of what the finished works would look like, the Ruskins bought two of the 1842 watercolours ( Lucerne from the Walls, National Museums and Galleries on Merseyside (Lady Lever Art Gallery, Port Sunlight), Wilton 1529, and Coblenz ('Ehrenbreitstein'), untraced, Wilton 1530) and two the following year ( Goldau, Private Collection, Wilton 1537, and The Pass of St Gothard, near Faido, Private Collection, Wilton 1538), also acquiring the 1842 Constance [Lake Lucerne], York City Art Gallery, Wilton 1531, in 1843.
A further group of ten watercolours (of which only nine seem to have been completed, Wilton 1540-1549) was painted on commission in 1845, the Ruskins buying three ( The Lake of Lucerne from above Brunnen. Sunset, Private Collection, Wilton 1543; Brunnen from the Lake of Lucerne, Sterling and Francine Clark Art Institute, Williamstown, Wilton 1545, and Storm in the St Gotthard Pass. The First Bridge over Altdorf, Whitworth Art Gallery, University of Manchester, Wilton 1546), and adding a fourth in 1846, Lucerne from the Lake, Private Collection ( Wilton 1544).
For a full account, see Warrell, Through Switzerland with Turner, Appendix II, pp.149ff.