Slike stranica
PDF
ePub

it is available for navigation only in the wet seasons. In Central Africa there seems to be a similar phenomenon between the eastern tributaries of Lake Tchad and the western tributaries of the Bahr el Abiad or White Nile, though this rests on the authority of the Arabs. In India there appears to be a similar connection between the middle course of the Indus and the Jumna, and so the Ganges, by the mediation of the Sarasvati or Histara and the Gharghara. There may have been the same in Central China, between the Hoang-ho and the Kiang, where the Imperial Canal now runs; and a similar feature may be found in the Lithuanian marshes, connecting the Vistula and Dnieper river systems, through the mediation of the Bug and the Przypec. The skill of man has, in many places, accomplished the same end by the construction of canals.

Although all rivers, in the course of their development, follow the universal law which leads them from their source, however high, to the sea, yet there is, even in their descent, scope for exceedingly varied phenomena. It is not necessary that everywhere a strongly-marked line of water-shed should exist, but often, as in all the more level plateaus, there are broad, neutral plains which perform the function of water-sheds, though possessing no decisive character. It is so through a great part of Central Asia, in the low plains of Australia, probably in a large part of Africa, and so markedly in America, that all lines of water-shed wholly disappear, and the rivers flow confusedly together, without any system, and in obedience to no law.

Some rivers come down the sides of high mountains in forrents, then course around in a long, winding course, urning out for all obstacles, and at last find the sea.

Others are entirely unlike them. The Ganges flows from the south side of the Himalaya Mountains, and courses along their base, following the direction of the chain in a southeasterly direction, till it reaches the Bay of Bengal. The Indus springs from the north side of the Himalaya, flows northwest over the plateau of Little Thibet as far as Iskardo, then breaks through the whole chain to pour itself out upon the lowlands of India, the Punjaub, and Mooltan. Dashing its way through the most formidable barriers, it is entirely unlike the gentle Ganges, which pursues its tranquil course through the plains, meeting no barrier in its entire length. The Indus, so long as it remains north of the Himalaya, traverses a plateau 10,000 feet above the sea; while the Ganges, even at Delhi, is but 1000 feet above the sea. Both rivers, although represented in precisely the same way upon the maps, have an entirely different physical character.

The same difference in structure occurs in the streams of other continents, and even in those of Central Europe, though on a less colossal scale. There are, therefore, classes of rivers, and they ought to be just as sharply discriminated as the classes in botany and zoology.

Plateau streams, such as the Danube, as far as the Lower Austrian and Hungarian plains, and the Saone, down to its confluence with the Rhone, pass through high, uniform plains with little fall. They are genuine mountain followers, springing from the verge of the chain and crossing along its base, the Saone taking the west side of the Alps, as the Danube does the northern, and the Po the southern.

The rivers which force their way through mountain ranges form a second class. The Rhine, a free child of the Alps, from its source to the sea, breaks through all

the ranges up to the Jura; then it forces a path through all the mountains of Central Germany, till it comes to its lower course. It may, therefore, be classified with the Indus. It leaves the Alps suddenly at Bâle, and opens a new and romantic way through no insignificant obstacle, and is everywhere a conqueror. That is the peculiarity of the Rhine.

Two streams of analogous nature, though less marked in their characteristics, are the Elbe and the Weser. But these both rise, not among the Alps, but amid the German mountains. They lack, therefore, the exceedingly romantic character of Alpine rivers; but they do not lack in picturesque scenery, and this they owe to the obstacles which they pass. The Elbe has broken its way from the Bohemian ridge through the so-called Saxon-Switzerland, as far as Meissen, and the Weser from the fissures of the Werra and the Fulda to the Porta Westphalica. The Elbe and the Weser make, with the Rhine, the triad of Central European rivers, which have broken a pathway for themselves through mountains which impeded their

course.

A third class of rivers are those which encounter no obstacles, and flow in a placid stream from the source to the mouth. They extend in Europe from the Vistula to the Ems, including the Oder and excluding the Weser and Elbe, and from the Rhine along the whole Atlantic coast of France, embracing the Seine, Loire, Garonne, and the Adour-all of these having, in greater or less degree, the same hydrographical character.

From these can be still further discriminated the subordinate coast rivers.

To a fourth class belong all those tributary streams, of whatever size or length, which agree in possessing no

independent character, and do not pour their waters into the sea through their own mouths.

The application of this system of classification can be applied to the streams and their accompanying terrace lands in the other continents. But these observations may suffice to indicate the general principles which we would apply to the study of rivers, and leave to the student their further application.

Review.

The great typical forms already considered, highland, plateau, mountain, lowland, terrace, and river, which all claim so large a share of attention in studying their physi cal characteristics, are no less worthy of careful attention, in consequence of their influence on human culture. Our account would not be complete without devoting a few pages to the consideration of the manner in which nature and history have reacted on each other.

The most elevated highlands, the loftiest plateaus, uniform in their aspect, immense in their extent, isolated, without trees, having the thin soil characteristic of steppes, and useful only for grazing, are the home of the primitive nomadic races. Without forests and without shelter, without valleys and without water-courses, with sandy and rocky soil, covered with a scanty vegetation, they serve only to supply food for the gregarious animals which follow man, and to furnish a home to wandering tribes of herdsmen. Instances are found in Central Asia, in Toorkistan and Persia, in Central Africa, including the Galla tribes and the Abyssinians. So, too, among the high plateaus of America, the home of the primitive Aztecs. From such places came the first movements of emigration; from the high plateaus of Central Asia came the wandering

Persians, Huns, Mongolians, and Turks; and the same. course of emigration was witnessed among the negro tribes of Central Africa, proceeding from the Galla tribes. The lower highlands, less colossal in size, of more moderate height, and of more genial temperature, have at all times reached a certain low stage of culture, after giving a home to the nomads from the higher plateau; but have never developed that culture to any considerable extent. We find examples of this in the high terraces of Bootan, the Deccan, and Persia; in Africa, among the Atlas mountains; in Abyssinia, in the ancient Greek Arcadia, in Castile, in Arvernia, (Auvergne,) in Gallia, in Hesse, in the Eifel, and on the Valdai hills.

In the exceedingly complex, subdivided, and romantic mountain districts of the globe, the races have attained, by virtue of the variety of their resources and the energy of their stock, to the highest results of civilization, and have manifested the most independent and progressive spirit. In such regions, hunting, working in wood, the settled life of shepherds, working in metals, agriculture on such terrace lands as those of Nepaul, Cashmere, Palestine, the Lebanon, Apennine, and other ranges, fruit culture, tilling vineyards, the cultivation of all kinds of industry, as in Central Germany and in most regions of the temperate zone, develop most thoroughly and speedily the culture of a people. In such occupations men learn to lean more on each other, and grow into that diversity of occupation and division of labor, which are the latest results of civilization. The Zend, the Sanscrit, and the Persian nations which people the fertile tracts at the base of the Himalaya Mountains, from Maghada, Lahore, Nepaul, and Cashmere, as far as Persepolis and Hamadan, Susa and Shiraz, the inhabitants of the hill country of Palestine and

« PrethodnaNastavi »