for the knowledge they gave him enabled him to fill out the slightest hints of his “breeding” subjects with an inexhaustible wealth of plausible detail. The National Gallery collection contains just on three hundred of Turner’s sketch books, and practically the whole of his work done immediately in the presence of nature. This data enables us to speak with absolute authority upon the difficult question as to the relation between Turner’s art and nature. They prove that he very seldom, if ever, painted a picture simply “out of his head.” In everything he did--even, I believe, in the case of what have been called his classical nonsense pictures--there was a nucleus of immediately perceived fact. This sensuous basis is seldom, if ever, absent from his work, but it is invariably overlaid and distorted by the purely subjective forces of the artist’s personality, which appropriate the data of sense, and mould them into any shape they choose. It is impossible, especially since “Modern Painters” was written, to overlook the important part played by natural fact in all of Turner’s creations, but it is just as important not to overlook the equally obvious and certain truth that Turner never uses nature simply for its own sake, but only as a means of expression. The methods employed in the particular case we have just studied are, with few exceptions, the methods which he adopted during the whole of his career. Yet Turner did undoubtedly upon occasion paint in oil directly from nature. An instance of this kind is described by Sir Charles Eastlake in “Thornbury” (p. 153, 3rd edition). Eastlake met Turner during his second visit to Devonshire, probably in the summer of 1813, and accompanied him to a cottage near Calstock, the residence of Eastlake’s aunt, where they stayed for a few days. Another artist was with them, a Mr. Ambrose Johns, of Plymouth. It was during their rambles in the neighbourhood of Calstock that Turner gathered the material for his picture of “_Crossing the Brook_.” Eastlake says that “Turner made his sketches in pencil and by stealth,” that is to say, he did not like to have people looking over his shoulder while he was at work. The sketch book Turner used on this occasion is with the others in the National Gallery. But after the three artists had returned to Plymouth, “in the neighbourhood of which he (Turner) remained some weeks, Mr. Johns fitted up a small portable painting-box, containing some prepared paper for oil sketches, as well as the other necessary materials. When Turner halted at a scene and seemed inclined to sketch it, Johns produced the inviting box, and the great artist, finding everything ready to his hand, immediately began to work. As he sometimes wanted assistance in the use of the box, the presence of Johns was indispensable, and after a few days he made his oil sketches freely in our presence. Johns accompanied him always; I was only with them occasionally. Turner seemed pleased when the rapidity