196. Pictures executed on such a system are not, properly speaking, works in _color_ at all; they are studies of light and shade, in which both the shade and the distance are rendered in the general hue which best expresses their attributes of coolness and transparency; and the lights and the foreground are executed in that which best expresses their warmth and solidity. This advantage may just as well be taken as not, in studies of light and shadow to be executed with the hand; but the use of two, three, or four colors, always in the same relations and places, does not in the least constitute the work a study of color, any more than the brown engravings of the Liber Studiorum; nor would the idea of color be in general more present to the artist's mind when he was at work on one of these drawings, than when he was using pure brown in the mezzotint engraving. But the idea of space, warmth, and freshness being not successfully expressible in a single tint, and perfectly expressible by the admission of three or four, he allows himself this advantage when it is possible, without in the least embarrassing himself with the actual color of the objects to be represented. A stone in the foreground might in nature have been cold gray, but it will be drawn nevertheless of a rich brown, because it is in the foreground; a hill in the distance might in nature be purple with heath, or golden with furze; but it will be drawn, nevertheless, of a cool gray, because it is in the distance. 197. This at least was the general theory,--carried out with great severity in many, both of the drawings and pictures executed by him during the period: in others more or less modified by the cautious introduction of color, as the painter felt his liberty increasing; for the system was evidently never considered as final, or as anything more than a means of progress: the conventional, easily manageable color, was visibly adopted, only that his mind might be at perfect liberty to address itself to the acquirement of the first and most necessary knowledge in all art--that of form. But as form, in landscape, implies vast bulk and space, the use of the tints which enabled him best to express them, was actually auxiliary to the mere drawing; and, therefore, not only permissible, but even necessary, while more brilliant or varied tints were never indulged in, except when they might be introduced without the slightest danger of diverting his mind for an instant from his principal object. And, therefore, it will be generally found in the works of this period, that exactly in proportion to the importance and general toil of the composition, is the severity of the tint; and that the play of color begins to show itself first in slight and small drawings, where he felt that he could easily secure all that he wanted in form.