Eleration.—With respect to height, it is a general rule that the A. are lowest where the system is broadest, that is, in the e., and highest where the system is narrowest, that is, towards the w. Making a threefold distinction of crests, summits, and passes, the principal ranges may be characterized as follows : The crest-line : (1) of west A., 6000 to 11,000 ft.; (2) of middle A., 9000 to 13.000 ft; (3) of east A., 3600 to 9000 ft. The sum mits ; (1) of west A., 9000 to 14,000 ft.; (2) of middle A., 9000 to 15,800 ft.; (3) of east A., 6000 to 12,000 ft. Height of the passes: (1) of west A., 4000 to 8000 ft. ; (2) of middle A., 6500 to 11,000 ft.; (c) of east A., 3500 to 6000ft.
A comprehensive classification leads to a division of the elevations into three regions; 1. The lower range forming the buttresses of the main masses, and reaching a height of 2500 to C000 ft. ; that is, to the extreme limit of the growth of wood. 2. The middle zone lying between the former limit and the snow-line, at the elevation of 8000 to 9000 ft. 3. The highA., rising to 15,744 ft. The middle zone forms the region of mountain-pastur ages, where the characteristic Alpine dairy-farming is carried on. These pastures con sist of a rich carpet of grass and flowers. This threefold division of heights, however, does not everywhere coincide with the same phenomena of vagetation: the line of per petual snow descends lower on the n. side, and the boundaries of the zones above de scribed vary accordingly. 1. The line of demarkation between the region of mosses and Alpine plants and that of perpetual snow, is from 8000 to 9000 feet on the northern de clivities; but on the southern it approaches 10,000 ft. 2. The highest limit to which wood attains on the n. is about 6000 ft. while on the s. it is nearly 7000 ft. 3. Grain, beech, and oak on the a. disappear at the elevation of 4000 ft.; on the s. they contrive to exist some hundreds of ft. higher. 4. The region of the vine, as well as of maize and chestnuts, extends to an elevation of 1900 ft. on the northern declivity, and on the south ern declivity to 2500 ft. The ranges of outlying lower mountains which flank the high central A. on the n., e., and w. are mostly wanting on the s., especially where the mid dle A. descend into the plains of Lombardy. Thus the A. rise in steep rocky precipices from the level of the flat plains of the Po, whilst they sink more gradually into the plains on the n.; hence their mighty masses closely piled together present an aspect from the
s. more grand and awful; from the n. more extended and various.
Valleys.—The variety of the valleys as to form and arrangement is not less striking than in the elevations. Most worthy of notice is the characteristic form of the wide longitudinal valleys that lie at the foot of the high central chains. On the e. side they open directly into the plain ; on the n. they are connected with the plain through transverse valleys which often end in lakes. The transverse valleys on the s. side are mostly in the shape of steep rocky ravines, forming in some parts lakes. Besides the deep-sunk principal valleys, there are extensive series of basin-shaped sec ondary valleys, which are the scenes of Alpine life, properly so called. Many of the Alpine valleys have names distinct from the rivers flowing through them. Thus, the valley of the Rhone is styled the upper and lower 'Valais; that of the Adda, tue Valte line ; of the Arve, Chamounix.
Communications—Passes.—The valleys of the high A. form the natural means of com munication. Some are more accessible than others. The entrance into a longitudinal valley is almost always smooth and easy; art has often had to force an entrance into a transverse valley. On many of the high-roads which link the principal with the second ary valleys, it has been found necessary to blow up long ridges of rock, to build terraces, to make stone-bridges and long galleries of rock as a protection against avalanches, as well as to erect places of shelter. (hawk* from storms. The construction of these roads may be reckoned among the boldest and most skillful works of man. In crossing the A., several defiles (usually seven) have to be traversed; for in addition to the pass of the main crest, there are other defiles on both sides at the entrance of the different valleys. In the c., the numher of these narrow passes or defiles is considerably increased. The names applied to the Alpine passes vary according to their natural features or the local dialect; as Pass Sattel (saddle), Joch (yoke) Scheideck, Klause, Col, Chiusa. The trav eler, in the course of a day's journey, experiences a succession of climatic changes, which is accompanied with an equal variety in the manners of the people.