§ 7. Neither the helmet cloud, nor the lee-side cloud, however, though most interesting and beautiful, are of much importance in picturesque effect. They are too isolated and strange. But the great mountain cloud, which seems to be a blending of the two with independent forms of vapor (that is to say, a greater development, in consequence of the mountain's action, of clouds which would in some way or other have formed anywhere), requires prolonged attention, as the principal element of the sky in noblest landscape. § 8. For which purpose, first, it may be well to clear a few clouds out of the way. I believe the true cumulus is never seen in a great mountain region, at least never associated with hills. It is always broken up and modified by them. Boiling and rounded masses of vapor occur continually, as behind the Aiguille Dru (lowest figure in Plate 69); but the quiet, thoroughly defined, infinitely divided and modelled pyramid never develops itself. It would be very grand if one ever saw a great mountain peak breaking through the domed shoulders of a true cumulus; but this I have never seen. § 9. Again, the true high cirri never cross a mountain in Europe. How often have I hoped to see an Alp rising through and above their level-laid and rippled fields! but those white harvest-fields are heaven's own. And, finally, even the low, level, cirrus (used so largely in Martin's pictures) rarely crosses a mountain. If it does, it usually becomes slightly waved or broken, so as to destroy its character. Sometimes, however, at great distances, a very level bar of cloud will strike across a peak; but nearer, too much of the under surface of the field is seen, so that a well-defined bar across a peak, seen at a high angle, is of the greatest rarity. [Illustration: J. Ruskin. J. C. Armytage. 70. The Graiæ.] [Illustration: 71. "Venga Medusa."] [Illustration: FIG. 87. _To face page 127._] § 10. The ordinary mountain cloud, therefore, if well defined, divides itself into two kinds: a broken condition of cumulus, grand in proportion as it is solid and quiet,--and a strange modification of drift-cloud, midway, as I said, between the helmet and the lee-side forms. The broken, quiet cumulus impressed Turner exceedingly when he first saw it on hills. He uses it, slightly exaggerating its definiteness, in all his early studies among the mountains of the Chartreuse, and very beautifully in the vignette of St. Maurice in Rogers's Italy. There is nothing, however, to be specially observed of it, as it only differs from the cumulus of the plains, by being smaller and more broken.