Easy, indeed, but not sure, even in cloud-color only. It is true that the smoke of a town may be of a rich brick red against golden twilight; and of a very lovely, though not bright, blue against shade. But I never saw crimson or scarlet smoke, nor ultramarine smoke. Even granting that watery vapor in its purity may give the colors more clearly, the red colors are by no means always relieved against light. The finest scarlets are constantly seen in broken flakes on a deep purple ground of heavier cloud beyond, and some of the loveliest rose-colors on clouds in the east, opposite the sunset, or in the west in the morning. Nor are blues always attainable by throwing vapor over shade. Especially, you cannot get them by putting it over blue itself. A thin vapor on dark blue sky is of a warm gray, not blue. A thunder-cloud, deep enough to conceal everything behind it, is often dark lead-color, or sulphurous blue; but the thin vapors crossing it, milky-white. The vividest hues are connected also with another attribute of clouds, their lustre--metallic in effect, watery in reality. They not only reflect color as dust or wool would, but, when far off, as water would; sometimes even giving a distinct image of the sun underneath the orb itself;--in all cases becoming dazzling in lustre, when at a low angle, capable of strong reflection. Practically, this low angle is only obtained when the cloud seems near the sun, and hence we get into the careless habit of looking at the golden reflected light as if it were actually caused by nearness to the fiery ball. [Illustration: 66. Light in the West, Beauvais.] § 19. Without, however, troubling ourselves at all about laws, or causes of color, the visible consequences of their operation are notably these--that when near us, clouds present only subdued and uncertain colors; but when far from us, and struck by the sun on their under surfaces--so that the greater part of the light they receive is reflected--they may become golden, purple, scarlet, and intense fiery white, mingled in all kinds of gradations, such as I tried to describe in the chapter on the upper clouds in the first volume, in hope of being able to return to them "when we knew what was beautiful." The question before us now is, therefore, What value ought this attribute of clouds to possess in the human mind? Ought we to admire their colors, or despise them? Is it well to watch them as Turner does, and strive to paint them through all deficiency and darkness of inadequate material? Or, is it wiser and nobler--like Claude, Salvator, Ruysdael, Wouvermans--never to look for them--never to portray? We must yet have patience a little before deciding this, because we have to ascertain some facts respecting the typical meaning of color itself; which, reserving for another place, let us proceed here to learn the forms of the inferior clouds. FOOTNOTES: [1] Before going farther, I must say a word or two respecting method of drawing clouds.