better devote a separate chapter. FOOTNOTES [66] So called from the mouldering nature of its rocks. They are slaty crystallines, but unusually fragile. [67] The materials removed from the slope are spread over the plain or valley below. A nearly equal quantity is supposed to be removed from the other side; but besides this _removed_ mass, the materials crumble heavily from above, and form the concave curve. [68] The lines are a little too straight in their continuations, the engraver having cut some of the curvature out of their thickness, thinking I had drawn them too coarsely. But I have chosen this coarsely lined example, and others like it, following, because I wish to accustom the reader to distinguish between the mere fineness of instrument in the artist's hand, and the precision of the line he draws. Give Titian a blunt pen, and still Titian's line will be a noble one: a tyro, with a pen well mended, may draw more neatly; but his lines ought to be discerned from Titian's, if we understand drawing. Every line in this woodcut of Durer's is _refined_; and that in the noblest sense. Whether broad or fine does not matter, the lines are _right_; and the most delicate false line is evermore to be despised, in presence of the coarsest faithful one. [69] Not absolutely on the meeting of the curves in one point, but on their radiating with some harmonious succession of difference in direction. The difference between lines which are in true harmony of radiation, and lines which are not, can, in complicated masses, only be detected by a trained eye; yet it is often the chief difference between good and bad drawing. A cluster of six or seven black plumes forming the wing of one of the cherubs in Titian's Assumption, at Venice, has a freedom and force about it in the painting which no copyist or engraver has ever yet rendered, though it depends merely on the subtlety of the curves, not on the color. [70] "_Out of_ perspective," I should have said: but it will show what I mean.