Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/658

Rh ALPS Thus if we take the great masses of the Himalaya in Asia, the Andes in South America, or even such lesser ranges as the Pyrenees or the Great Atlas, we find that they interpose a far more absolute limit between the regions lying on their opposite flajiks than occurs in respect to the Alps. These are formed of numerous ranges divided by comparatively deep valleys, which, with many local excep tions, tend towards parallelism with the general direction of the entire mass. This, between Dauphin6 and the borders of Hungary, forms a broad band convex towards the north, and most of the main valleys lie between the directions west to east and south-west to north-east. But in many parts deep transverse valleys intersect the pre vailing direction of the ridges, and facilitate the passage not only for purposes of human intercourse, but also for the migration of animals and plants, and for currents of air which mitigate the contrast that would otherwise be found between the climates of the opposite slopes. The received opinion is, that the name Alps is derived from a Celtic root alp or alb signifying height. This has been connected by some writers with the Latin alb, albus, white, referring to the colour of the peaks. Strabo says that the name &quot;AA-Trta was formerly &quot;AA.y8ta. Alp in south Germany alpa in old High German is exclusively applied to mountain pastures. For the present the deriva tion must remain somewhat uncertain. To define the precise limits of the Alps, as will be seen fully in describing the several groups, is a somewhat arbi trary operation. To the W. they extend through a large portion of the French departments of Savoie, Haute-Savoie, Ilautes Alpes, and Basses Alpes, being divided from the mountain district of the Cevennes by the broad and deep valley through which the Rhone flows from Lyons to the Mediterranean. The Jura range, usually regarded as distinct from the Alps, is nevertheless closely connected on one side with the outer ranges of the Alps of western Savoy, and on the other with those of northern Switzer land. On the N. side the Alps are definitely bounded by the lake of Constance, the plain of Bavaria, and the low country extending from Salzburg to the neighbourhood of Vienna. By these they are completely separated from the mountainous districts of central Germany, which extend through western Bohemia and Saxony in one direction to the Hartz mountains, and in the other to the Sudeten, or Riesengebirge, of Silesia. Hence it happens that the drainage of the northern slopes of the Alps flows either to the North Sea through the Rhine, or is diverted through the Danube to the Black Sea, and no portion of it reaches the Baltic. The eastern limit of the Alps is not easily defined with accuracy. The region of high hills, chiefly formed of tertiary strata, that extends from the left bank of the Mur into Hungary is continued by the north side of Lake Balaton to the Danube near Buda ; and some geographers see in the hilly district that stretches thence to the northern Carpathians a connection between that range and the Alps. For practical purposes it seems that the line of depression, partly formed by the valley of the Mur, through which the railway is carried from Vienna to Laybach, may be considered as the eastern boundary of the Alpine chain. On the southern side the difficulty of fixing the precise limits of the Alpine chain is still more apparent. For a distance of some 350 miles, from the neigh bourhood of Turin to that of Gorizia, the boundary is sufficiently obvious! The mountains subside into the con tinuous plain which includes the greater part of Piedmont, Lombardy, and Venetia; and their drainage is all borne eastward to the Adriatic. But on the west side of Piedmont the Alpine chain dividing Italy from France extends nearly due southward till it approaches to the Mediterranean in the neighbourhood of Xice. About 40 miles north of this city, that which, from its superior height and its geological struc ture, we call the main chain, is bent round from west to cast in a curve, slightly convex towards the south, till it becomes parallel to the Mediterranean shore, and is merged in the chain of the Apennines. For reasons hereafter mentioned it would appear that the limits of the Alps in this direction may best be fixed at the Col d Altare, west of Savona, though the boundary commonly adopted is that of the Col di Tenda, lying considerably farther to the west. At the south eastern extremity of the Alpine chain the difficulty of fixing its limits arises rather from the vague use of geographical terms by ancient and modern writers than from the physical structure of the region. Taking no account of the arbitrary proceedings of geographers who have included in the Alps the mountains dividing Bosnia from Croatia and Dalmatia, and regarding only the natural features of the country, it seems clear that the south-eastern extremity of the Alps must be looked for in the group of lofty peaks between the head waters of the Isonzo and those of the Save, whose highest summit is the Terglou ; and if we are not to include all the mountain ranges of European Turkey and Greece within the same designation, the plateau of the Karst must be held to form the boundary between these and the Alp.s. Within these limits the Alps extend from about the 44th to the 48th parallel of N. lat., and from about 5 10 to 18 10 E. long. In every mountain system geographers are disposed to Main cl regard the watershed, or boundary dividing the waters of the A flowing towards opposite sides of the range, as marking the main chain ; and this usage is often justified by the fact that the highest peaks lie on, or very near, the boundary so defined. In applying this term in the case of the Alps, there are, however, difficulties arising from their great extent and the number of their branches and ramifications. Many of the loftiest groups lie altogether on one side of that which we call the main chain, and at the eastern extremity, where all the drainage is ultimately borne to the Black Sea, we must be partly guided by geological considerations in deciding which of several ranges deserves to be considered pre-eminent. Starting from the pass of Altare or Cadibona, west of Savona, the main chain extends first south-west, then nearly due west, to the Col di Tenda, but nowhere rising beyond the zone of coniferous trees. Beyond that limit the range is more lofty, and includes four peaks exceeding 10,000 feet in height, till the line dividing the water.-; flowing to the Adriatic, through the Po, from the short streams that flow into the Gulf of Genoa, reaches the Mont Enchastraye. Beyond that point, although the line of watershed is very sinuous, its general direction for a distance of about 75 miles is nearly due north. On the east side the waters run to the Po ; on the west they flow through the Durance to join the Rhone near Avignon. The most considerable peaks in the range immediately north of the Mont Enchastraye are the Grand Rioburcnt and the Aiguille de Chambeyron ; but these are much surpassed by the Monte Viso, which is the highest peak in the range dividing Piedmont from Dauphine&quot;. On the north side of Monte Viso the main chain diminishes much in average height, and presents no prominent peaks until we reach the Mont Tabor. That summit forms the apex of a salient angle which the main chain here presents on the side of France. For a distance of about 28 miles this extends eastward to the prominent peak of the Roche- Melon, which may be considered as a re-entering angle in the great rampart by which Italy is guarded from her northern neighbours. Here the main chain resumes its northerly direction, and attains a greater average height than it had previously exhibited. Several of the prominent peaks in the range connecting the Roche Melon with Mont