71. Let me notice, in passing, the infinite absurdity of ever hanging Venetian pictures above the line of sight. There are very few persons in the room who will be able to see the drawing of this bird's beak without a magnifying-glass; yet it is ten to one that in any modern gallery such a picture would be hung thirty feet from the ground. Here, again, is a little bit to show Carpaccio's execution. It is his signature: only a little wall-lizard, holding the paper in its mouth, perfect; yet so small that you can scarcely see its feet, and that I could not, with my finest-pointed brush, copy their stealthy action. 72. And now, I think, the members of my class will more readily pardon the intensely irksome work I put them to, with the compasses and the ruler. Measurement and precision are, with me, before all things; just because, though myself trained wholly in the chiaroscuro schools, I know the value of color; and I want you to begin with color in the very outset, and to see everything as children would see it. For, believe me, the final philosophy of art can only ratify their opinion that the beauty of a cock robin is to be red, and of a grass-plot to be green; and the best skill of art is in instantly seizing on the manifold deliciousness of light, which you can only seize by precision of instantaneous touch. Of course, I cannot do so myself; yet in these sketches of mine, made for the sake of color, there is enough to show you the nature and the value of the method. They are two pieces of study of the color of marble architecture, the tints literally "edified," and laid edge to edge as simply on the paper as the stones are on the walls. 73. But please note in them one thing especially. The testing rule I gave for good color in the "Elements of Drawing," is that you make the white precious and the black conspicuous. Now you will see in these studies that the moment the white is inclosed properly, and harmonized with the other hues, it becomes somehow more precious and pearly than the white paper; and that I am not afraid to leave a whole field of untreated white paper all round it, being sure that even the little diamonds in the round window will tell as jewels, if they are gradated justly. Again, there is not a touch of black in any shadow, however deep, of these two studies; so that, if I chose to put a piece of black near them, it would be conspicuous with a vengeance. But in this vignette, copied from Turner, you have the two principles brought out perfectly. You have the white of foaming water, of buildings and clouds, brought out brilliantly from a white ground; and though part of the subject is in deep shadow the eye at once catches the one black point admitted in front.