Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/659

Rh ALPS 621 Blanc exceed 11,000 English, feet in height, though they are much surpassed by the highest group of the Graian Alps, lying on the side of Piedmont, and that of the Tarentaise Alps in Savoy ; while there is in this part of the main range but one considerable depression, which is that crossed by the road of th e Little St Bernard. In the range crowned by the summit of Mont Blanc the Alpine chain attains its highest elevation. From thence to the Pass of St Gotthard its general direction varies between east and north-east. To the east of Mont Blanc a comparatively low tract allows of several comparatively easy passes between Switzerland and Piedmont, one of which has long been famous as the Pass of the Great St Bernard ; but from that to the Simplon Pass, a distance of about 52 miles in a straight line, or about 75 miles if measured along the o / O watershed, the main chain preserves a greater average height than in any other part. Several peaks lying in the dividing ridge, such as the Grand Combin, Matterhorn, Lyskamm, and Monte Rosa, exceed 14,000 feet in height; and these are rivalled by at least six summits on the north side of the same ridge, which at two points only sinks below the level of 10,000 feet. The Simplon Pass corre sponds to what may be called a dislocation of the main chain. From thence to the St Gotthard the dividing ridge runs nearly due north-east, and does not present any dominant summit excepting the Monte Leone. On the east and south-east side of the St Gotthard Pass, as far as that of the Maloya, the line of watershed between the affluents of the Rhine and that of the Po is determined by what may be called accidental conditions. The chief mountain ridges, which culminate in the Cima Camadra, Piz Valrhein, and Tambohorn, instead of being arranged along the parting of the waters, lie in a transverse direc tion, and hence the natural frontier of Italy is here more broken and irregular than elsewhere ; and it is only on the south side of the Maloya Pass that the main chain assumes a tolerably continuous direction from west-south-west to east-north-east, as between Piz Giiz and the Bernina Pass it rises into the lofty group whose dominant peaks are Piz Tremoggia, Piz Bernina, and Piz Cambrena. East ward of the Bernina Pass the same direction is preserved, and in the range including the Corno di Campo, Monte Zembrasca, and Monte Foscagno the level scarcely sinks below 9000 feet ; but beyond the last-named summit, in the space lying between the Lower Engadine, the head waters of the Adige, and those of the Adda, the semblance of a continuous ridge forming the watershed between the Inn and the Adriatic altogether disappears. If we adhere to the usage of designating as the main chain the ridges which part the waters flowing in different directions, it must be owned that the disposition of the chief mountain masses has no connection with the direction of that chain. Lying between the great mass of the Orteles Alps to the south and the considerable group of the Silvretta Alps on the north side of the Inn, the greater part of the mass in question is drained by streams that flow into the latter river; but the arrangement of the valleys seems to be largely due to erosive action. Few summits in this part of the main chain exceed 10,000 feet, the highest being Piz Scesvenna, on the east side of Val Scarla. The break in the continuity of the Alpine chain marked by the deep valley through which the main branch of the Adige descends, first southward and then eastward from its source to Meran and Botzen, is one of the most remark able features in the orography of the Alps. The little lake which is regarded as the chief source of the river lies within .less than five miles of the Inn, where that river enters the Tyrol, and no apparent barrier divides the lake from the Inn valley. Eastward of this limit the Alpine chain exhibits a degree of order in its general arrange which it is impossible to trace in its western and central portions. For a distance of some 250 miles a broad zone of crystalline rocks extends from west to east, flanked on the north and south sides by parallel zones of sedimentary rocks, chiefly belonging to the older secondary formations. Two great valley systems on the opposite sides of the central zone closely coincide with those geological boundaries, and mark out in the physical aspect of this region the limits between the central and the secondary zones. In the former are situated all the highest peaks of the eastern Alps. For a distance of about 140 miles, from the Schafkogel, south-east of Nauders, to the Markkahrspitz, the average level of the main chain is nearly as high as in any equally long section of the central or western Alps. There is one very con siderable depression which is marked by the Brenner Pass, but elsewhere in that long barrier there are but three points where the range is passable by beasts of burden. Between the two main sources of the Adige, at the Reschen Scheideck and the Brenner Pass, the considerable groups of the Oetzthal and Stubay Alps attain a great average elevation, though two points only the Wildspitz and the Weisskugel surpass the level of 12,000 feet. The drainage of these groups is mostly carried to the Inn, and the line of watershed, about 53 miles in length, is much less direct than in the more easterly portion of the chain. This extends nearly due east for about 90 miles from the Brenner Pass, nowhere falling below the level of 8000 feet, and in two prominent peaks the Gross Venediger and the Gross Glockner rising considerably above the limit of 12,000 feet. At a point somewhat north of the Mark kahrspitz the central chain divides into two parallel ranges, between which lies the upper valley of the Mur. This river flows for a distance of fully 80 miles nearly due east, till at Bruck-an-der-Mur it turns southward to approach the Drave, and ultimately joins that stream. Various reasons combine to induce geographers to regard the more northern of the two ranges above mentioned, which divides the Enns and other minor tributaries of the Danube from those of the Drave, as constituting the eastern extremity of the main chain of the Alps. This extends a little north of due east for more than 110 miles, with a comparatively low mean elevation, from the Arlscharte to the Scmmering Pass, which we regard as the eastern limit of the main chain of the Alps. Measured along the watershed, as above defined, but without taking into account the minor sinuosities, which would considerably increase the total, the length of the main chain is about 790 English miles. For ages before there existed any correct knowledge of Passes c the configuration of the Alpine chain, the needs of war and ike Alp commerce had urged the people dwelling on the opposite sides of the great barrier to seek out the easiest and most direct routes for traversing it. Hence the chief passes of the Alps have been known and frequented from a period antecedent to authentic history, while until a quite modern period little attention was given to the parts of the chain which did not lie in or near the lines of traffic. It is highly probable that many other passes, affording the easiest means of communication between adjacent valleys, have been known and used by the native population from a very remote period, but only those which served for international purposes of war or peace became known at a distance, and are alluded to by ancient writers. A pass is a depression between two adjacent mountains, and the track is usually carried over the lowest part of that depres sion ; but nevertheless nearly all the passes of the Alps involve a long ascent to reach the summit, and a long descent upon the opposite slopes. Hence the Romans, who were the first semi-civilised people to make extensive