Modern Painters, Volume 4 (of 5)

by John Ruskin

§ 9. One way in which she gets it is curiously simple in itself, but somewhat difficult to explain, unless the reader will be at the pains of making a little model for himself out of paste or clay. Hitherto, observe, we have spoken of these crests as seen at their sides, as a Greek helmet is seen from the side of the wearer. By means presently to be examined, these mountain crests are so shaped that, seen in front, or from behind (as a helmet crest is seen in front of or behind the wearer), they present the contour of a sharp ridge, or house gable. Now if the breadth of this ridge at its base remains the same, while its height gradually diminishes from the front of it to the back (as from the top of the crest to the back of the helmet), it necessarily assumes the form of such a quaint gable roof as that shown in profile in [Fig. 50], and in perspective[70] in [Fig. 51], in which the gable is steep at the end farthest off, but depressed at the end nearest us; and the rows of tiles, in consequence, though in reality quite straight, appear to radiate as they retire, owing to their different slopes. When a mountain crest is thus formed, and the concave curve of its front is carried into its flanks, each edge of bed assuming this concave curve, and radiating, like the rows of tiles, in perspective at the same time, the whole crest is thrown into the form [Fig. 52], which is that of the radiating plume required.

Fig. 52.

Fig. 53.

§ 10. It often happens, however, that Nature does not choose to keep the ridge broad at the lower extremity, so as to diminish its steepness. But when this is not so, and the base is narrowed so that the slope of side shall be nearly equal everywhere, she almost always obtains her varied curvature of the plume in another way, by merely turning the crest a little round as it descends. I will not confuse the reader by examining the complicated results of such turning on the inclined lines of the strata; but he can understand, in a moment, its effect on another series of lines, those caused by rivulets of water down the sides of the crest. These lines are, of course, always, in general tendency, perpendicular. Let a, [Fig. 53], be a circular funnel, painted inside with a pattern of vertical lines meeting at the bottom. Suppose these lines to represent the ravines traced by the water. Cut off a portion of the lip of the funnel, as at b, to represent the crest side. Cut the edge so as to slope down towards you, and add a slope on the other side. Then give each inner line the concave sweep, and you have your ridge c, of the required form, with radiant curvature.

§ 11. A greater space of such a crest is always seen on its concave than on its convex side (the outside of the funnel); of this other perspective I shall have to speak hereafter; meantime, we had better continue the examination of the proper crest, the c of [Fig. 48], in some special instance.

The form is obtained usually in the greatest perfection among the high ridges near the central chain, where the beds of the slaty crystallines are steep and hard. Perhaps the most interesting example I can choose for close examination will be that of a mountain in Chamouni, called the Aiguille Bouchard, now familiar to the eye of every traveller, being the ridge which rises, exactly opposite the Montanvert, beyond the Mer de Glace. The structure of this crest is best seen from near the foot of the Montanvert, on the road to the source of the Arveiron, whence the top of it, a, presents itself under the outline given rudely in the opposite plate ([33]), in which it will be seen that, while the main energy of the mountain mass tosses itself against the central chain of Mont Blanc (which is on the right hand), it is met by a group of counter-crests, like the recoil of a broken wave cast against it from the other side; and yet, as the recoiling water has a sympathy with the under swell of the very wave against which it clashes, the whole mass writhes together in strange unity of mountain passion; so that it is almost impossible to persuade oneself, after long looking at it, that the crests have not indeed been once fused and tossed into the air by a tempest which had mastery over them, as the winds have over ocean.

§ 12. And yet, if we examine the crest structure closely, we shall find that nearly all these curvatures are obtained by Nature's skilful handling of perfectly straight beds,—only the meeting of those two waves of crest is indeed indicative of the meeting of two masses of different rocks; it marks that junction of the slaty with the compact crystallines, which has before been noticed as the principal mystery of rock structure. To this junction my attention was chiefly directed during my stay at Chamouni, as I found it was always at that point that Nature produced the loveliest mountain forms. Perhaps the time I gave to the study of it may have exaggerated its interest in my eyes; and the reader who does not care for these geological questions, except in their direct bearing upon art, may, without much harm, miss the next seven paragraphs, and go on at the twenty-first. Yet there is one point, in a Turner drawing presently to be examined, which I cannot explain without inflicting the tediousness even of these seven upon him.

J. Ruskin.	R. P. Cuff.
33. Leading Contours of Aiguille Bouchard.

§ 13. First, then, the right of the Aiguille Bouchard to be called a crest at all depends, not on the slope from a to b, [Plate 33], but on that from a to h. The slope from a to b is a perspective deception; b is much the highest point of the two. Seen from the village of Chamouni, the range presents itself under the outline [Fig. 54], the same points in each figure being indicated by the same letters. From the end of the valley the supremacy of the mass b c is still more notable. It is altogether with mountains as with human spirits, you never know which is greatest till they are far away.

Fig. 54.