On the other hand, if divided by parallel lines, so as to look more or less like spun-glass, I call it striated. In Plate 69, Fig. 4, the top of the Aiguille Dru (Chamouni) is seen emergent above low striated clouds, with heaped massive cloud beyond. I do not know in the least what causes this striation, except that it depends on the nature of the cloud, not on the wind. The strongest wind will not throw a cloud, massive by nature, into the linear form. It will toss it about, and tear it to pieces, but not spin it into threads. On the other hand, often without any wind at all, the cloud will spin itself into threads fine as gossamer. These threads are often said to be a prognostic of storm; but they are not produced by storm. [Illustration: J. Ruskin J.C. Armytage 63. The Cloud-Flocks.] § 3. In the first volume, we considered all clouds as belonging to three regions, that of the cirrous, the central cloud, and the rain-cloud. It is of course an arrangement more of convenience than of true description, for cirrous clouds sometimes form low as well as high; and rain sometimes falls high as well as low. I will, nevertheless, retain this old arrangement, which is practically as serviceable as any. Allowing, also, for various exceptions and modifications, these three bodies of cloud may be generally distinguished in our minds thus. The clouds of upper region are for the most part quiet, or seem to be so, owing to their distance. They are formed now of striated, now of massive substance; but always finely divided into large ragged flakes or ponderous heaps. These heaps (cumuli) and flakes, or drifts, present different phenomena, but must be joined in our minds under the head of central cloud. The lower clouds, bearing rain abundantly, are composed partly of striated, partly of massive substance; but may generally be comprehended under the term rain-cloud. Our business in this chapter, then, is with the upper clouds, which, owing to their quietness and multitude, we may perhaps conveniently think of as the "cloud-flocks." And we have to discover if any laws of beauty attach to them, such as we have seen in mountains or tree-branches. § 4. On one of the few mornings of this winter, when the sky was clear, and one of the far fewer, on which its clearness was visible from the neighborhood of London,--which now entirely loses at least two out of three sunrises, owing to the environing smoke,--the dawn broke beneath a broad field of level purple cloud, under which floated ranks of divided cirri, composed of finely striated vapor. It was not a sky containing any extraordinary number of these minor clouds; but each was more than usually distinct in separation from its neighbor, and as they showed in nearly pure pale scarlet on the dark purple ground, they were easily to be counted.