19. Here is the most ordinary component of a foreground for instance, a pleasantly colored stone. Any of its pure outlines are not only without beauty, but absolutely powerless to give you any notion of its character, although that character is in itself so interesting, that here Turner has made a picture of little more than a heap of such stones, with blue water to oppose their color. In consequence of these difficulties and insufficiencies, most landscape-painters have been tempted to neglect outline altogether, and think only of effects of light or color on masses more or less obscurely defined. They have thus gradually lost their sense of organic form, their precision of hand, and their respect for limiting law; in a word, for all the safeguards and severe dignities of their art. And landscape-painting has, therefore, more in consequence of this one error than of any other, become weak, frivolous, and justly despised.
20. Now, if any of you have chanced to notice at the end of my "Queen of the Air," my saying that in landscape Turner must be your only guide, you perhaps have thought I said so because of his great power in melting colors or in massing light and shade. Not so. I have always said he is the only great landscape-painter, and to be your only guide, because he is the only landscape-painter who can draw an outline.
His finished works perhaps appear to you more vague than any other master's: no man loses his outlines more constantly. You will be surprised to know that his frankness in losing depends on his certainty of finding if he chooses; and that, while all other landscape-painters study from Nature in shade or in color, Turner always sketched with the point.
"Always," of course, is a wide word. In your copying series I have put a sketch by Turner in color from Nature; some few others of the kind exist, in the National Gallery and elsewhere. But, as a rule, from his boyhood to the last day of his life, he sketched only with the fine pencil point, and always the outline, more if he had time, but at least the outline, of every scene that interested him; and in general, outline so subtle and elaborate as to be inexhaustible in examination and uncopiable for delicacy.