Nor has the work of his later years always been understood in our days. Not many years ago a distinguished German oculist read a paper at the Royal Institution which was afterwards published in which he endeavoured to prove that what he considered eccentricities of colour in Turner’s later oil pictures were due--not to his attempts to paint the unpaintable--but to a senile affection of his eyes, which caused an unnatural distortion of his vision to yellow in everything. But Professor Liebreich can hardly have been aware that although the oil pictures upon which he rested his theory, being mainly attempts to depict objects or scenery seen in full sunlight, necessarily tended towards yellow as their prevailing colour, yet at the very same time, and up to his death, Turner was daily producing the sanest, most delicate, most refined water-colour drawings in the palest as well as the deepest tones of every colour on his palette! All the Swiss, Venetian and other sketches of 1838 to 1845, which are the crowning glory of the Water-Colour Rooms in Trafalgar Square, were executed during the period when, according to Professor Liebreich, Turner’s sight was permanently and hopelessly affected! No doubt he recognised that water-colour was unsuited as a medium for his new aim at painting pure light, and confined himself accordingly, for such subjects, to oil painting. The attacks of the critics, however, had had their effect on the public, and Turner in his later years began to find difficulty in selling even his drawings. Ruskin, in his “Notes on his Drawings Exhibited at the Fine Arts Society, 1878,” tells with inimitable charm and pathos how the old painter, returning in the winter of 1842 from a tour in Switzerland, brought back with him a series of important sketches, fourteen of which he placed, as was his custom, in the hands of Griffiths, his agent, with a view to the latter’s obtaining commissions for _finished_ drawings of each. Although the price asked for a large finished drawing was only eighty guineas, and notwithstanding the great beauty of the sketches, nine commissions only could be obtained. Ruskin, his father, Munro of Novar, and Bicknell of Herne Hill, all chose one or more, but other former patrons saw in them what they regarded as a new style, and declined them. Thirty years after, Ruskin--with pride for Turner’s sake, he tells us--sold his _Lucerne Town_ for a thousand guineas; it has since changed hands at two thousand. The _Lake of Constance_, which at the time no one would buy, was given to Griffiths in lieu of his commission; it fetched two thousand three hundred guineas at Christie’s in 1907! After 1845 Turner’s health gradually failed; he continued to work at his oil paintings up to his death in 1851, but, so far as is known, he executed comparatively few water-colour sketches or drawings during his last years.