ページの画像
PDF
ePub

RIVER SYSTEMS OF THE EASTERN CONTINENT.

35

Neckar and Mayne on the right bank, and the Aar and Moselle Eastern hemisphere. Of the other considerable rivers in the on the left.

north of Asia are the Yenesei (2,900 miles) and the Lena 268. Of the other considerable rivers flowing into the At-(2,400 miles). The Obi, Yenesei, and Lena all rise in the lantic Ocean are—the Elbe (690 miles) and the Weser (380 mountains of the Altai system, and flow through the Siberian miles) to the north, and the Meuse (550 miles), Seine (430 plain. Owing to the severity of the climate their waters are miles), Loire (570 miles), and Garonne (350 miles), to the frozen during a great part of the year, and they are hence of south. Spain is watered by numerous rivers, as the Minho little use for the purposes of navigation. (200 miles), the Douro (160 miles), the Tagus (510 miles), and 274. The Ganges (1,460 miles) and the Indus (1,700 miles), the Guadiana (450 miles); they are all navigable in the lower two of the most important rivers of Asia, both water the parts of their courses. The Guadalquiver (290 miles) is navi- northern portion of Hindoostan. The Ganges, whose basin gable for large vessels up to Seville.

extends from east to west to the south of the Himalaya Mount269. The rivers which flow into the Mediterranean have ains, flows in an easterly direction into the head of the Bay of generally short courses, owing to the nearness of the mountains Bengal. At its mouth it divides into numerous arms, which on the north. The Ebro (420 miles) flows from the eastern inclose a delta of immense extent (page 30): its most western side of the Spanish table-land. The Rhone (490 miles) rises in arm, called the Hoogly, upon which Calcutta is built, is the the highest region of the Alps, and passing in its course only one that is usually navigated. The Ganges is remarkable through Lake Geneva, below which it is navigable, falls into for the great extent of its fall: it is ascended by steamers as the Gulf of Lyons. The Arno (150 miles) and the Tiber (210 high as Allahabad, more than 800 miles from its mouth. miles) both water the western side of the Italian peninsula; 275. The Indus rises on the plateau of Tibet, to the north. the Po (450 miles) and the Adige (250 miles) flow through the ward of the Himalaya Mountains, at an elevation of more than plain of Lombardy, and enter the Adriatic Sea near its northern 15,000 feet, and flows into the Arabian Sea. About 470 miles extremity.

above its mouth the Indus receives on its left bank the river 270. Of the rivers Nowing into the Baltic Sea are—the Duna Chenaub, which collects the waters of the five streams of the (450 miles), the Niemen (400 miles), the Vistula (630 miles), Jeloam, the Chenaub, the Ravee, the Bayas, and the Sutlej and the Oder (550 miles). The Duna, the Vistula, and the The district watered by these five rivers is called the Punjaub.* Oder are navigable for the greater part of their courses. The | All the chief tributaries of the rivers, as well as the main Neva, which flows into the head of the Gulf of Finland, though stream, are navigable through nearly their entire length; only 46 miles in length, is of considerable importance, and bas steamboats of considerable size can ascend to more than 500 a vast vo

of water, since it is the outlet of the great lakes miles distance from the sea, an smaller vessels to 1,000. of Ladoga and Onega: it has a mean breadth of 1,500 feet 276. Of the other principal rivers belonging to the basin of and a depth of 50 feet, but is frozen over for five months of the Indian Ocean are the Saleun and the Irawaddy (1,200

miles), both flowing into the Gulf of Martaban; the Brahma271. The White Sea and Arctic Ocean receive several im- pootra, the Godavery, the Krishna, and the Cauvery, into the portant streams; among which are the Dwina (760 miles), the Bay of Bengal; the Nerbudda into the Gulf of Cambay; and Mezen (480 miles), and the Petchora (500 miles).

the united Euphrates (1,600 miles) and Tigris (980 miles) into the Persian Gulf.

the year.

[graphic]
[blocks in formation]

RIVER SYSTEMS OF THE EASTERN CONTINENT—(CONTINUED).

272. Asiatic RIVERS.—The rivers of Asia may, like those of Europe, be divided into two principal classes, separated by the mountains and table-lands which extend east and west through the interior. The northern division embraces the rivers which flow into the Arctic Ocean, and those (in the west) which terminate in inland seas or lakes unconnected with the ocean. The other and more numerous class includes the streams which have their origin in the mountains of the in

RIVER TIGRIS, AT BAGDAD. terior, and flow either southerly into the Indian Ocean, or east- 277. The seas to the east of Asia receive several large rivers, wardly into the Pacific.

among which are the Amour (2,300 miles), which flows into 273. The Obi, which flows into the Arctic Ocean, is 2,530 the Gulf of Tartary; the Hoang-Ho (2,600 miles), and the miles in length; its river-basin is 1,250,000 square miles in Yang-tse-Kiang (3,200 miles), both flowing into the Yellow extent, being probably the largest basin of any river in the Sea; and the Cambodia (2,000 miles), into the Gulf of Siam.

Questions.–269. Other considerable rivers flowing into the Atlantic Ocean? Rivers of Spain? 269. What is said of the rivers flowing into the Mediterranean? The Ebro ? Rhone ? Other streams? 270. The principal rivers flowing into the Baltic Sea ? Which are navigable? The Neva? 271. Streams flowing into the White Sea and Arctic Ocean? 272. How may the rivers of Asia be divided? The northern division ? The other class ? 278. The Ooi? Other considerable rivers of northern Asia ?

Questions.- What further is said of the Obi, Yenesei, and Lena? 274. The Ganges and Indus? Give particulars of the Ganges. 273. The Indus. Its tributaries? How far navigable? 276. Name the principal rivers belonging to the basin of the Indian Ocean 277. Those flowing into the eastern seas.

• Properly, Peenjab, or five rivers.

278. The drainage of a large part of the Asiatic continent, Gariep or Orange. Both the Senegal (900 miles) and the probably not less than four and a half millions of square miles- Gambia (650 miles) are navigable rivers; they flow in a westis unconnected with any of the surrounding oceans, but is re- erly direction, and draw their waters from the same mountain ceived into inland seas or lakes, of which the Caspian and Aral ranges in which are the sources of the Niger. The Gariep or possess the most extended basins. The principal continental Orange River, in the southern part of Africa, has a length rivers of Asia are the Kour (550 miles), the Amoo or Jihon of upward of 1,000 miles. The principal river upon the (1,300 miles), and the Sihoon (1,150 miles), flowing into the eastern side of Africa is the Zambesi, which brings down a Sea of Aral. The Tarim or Erghue (900 miles) flows into the great volume of water, and is said to be navigable for boats Lake of Lop, in the center of the continent. The Helmund through a distance of more than 900 miles. The Lufiji, Juba, (600 miles), which rises in the plateau of Afghanistan, falls and

many

other rivers of the eastern coast, have not been exinto Lake Zurrah; and the Jordan, in Palestine, into the plored, and are but little known. Dead Sea.

279. AFRICAN RIVERS.—The Nile is the most considerable river of Africa: it carries off the waters from the northern and western sides of the plateau and mountains of Abyssinia, and discharges itself into the Mediterranean. The Nile is formed

LESSON X. by the junction in latitude 15° 40' north) of two streams,—the

LAKES. Bahr-el-Azrek (Blue River), and the Bahr-el-Abiad (or White River): the latter is generally admitted to constitute the main 283. FRESH-WATER lakes occur in the greatest numbers, and channel of the river. The wonderful secret of the source of upon the largest scale, in the northern regions of the globe. the Nile, for centuries a geographical mystery, has lately been Nearly all the lakes of any considerable extent in North Amerunraveled by the intrepid and successful travelers, Speke, Bur- ica are situated north of the 40th parallel, while in Europe and ton, and Grant. It rises in an extensive lake called Victoria Asia, the regions peculiarly characterized by fresh-water colNyanza, lying beneath the equator. A short distance of the lections are, for the most part, north of the 50th parallel. Saltcourse of the river remains unexplored; but its origin is no water lakes have a more southerly distribution, and are very longer doubtful.

abundant in eastern Europe, and central and southern Asia. 280. Though the Nile has so great a length of course,

-prob- 284. Lakes may be divided into four classes, according to ably not much short of 3,500 miles—its basin is of very limited certain physical peculiarities. The first class includes those extent. For a distance of 1,400 miles above its mouth it re- which have no outlet, and do not receive any running water. ceives no tributary. Through the middle and lower portion of Lake Albano, near Rome, is an example. Many of these lakes its course, the Nile flows in a narrow valley inclosed on either are situated in elevated districts, and are generally small; it has side by steep rocks; the width of this valley varies from one to been supposed that they are the craters of extinct volcanoes, two miles in Nubia and Upper Egypt to as many as ten or and are supplied by springs. twelve miles lower down the stream.

285. The second class comprises those which receive water, 281. The Niger (or Quorra) is the largest of the African but have no apparent outlets. The Caspian Sea and Lake Aral rivers which flows into the Atlantic Ocean. It rises in the belong to this division. The Caspian is about 600 miles long ; mountains of Soudan, where the main tributary is known as the its extreme breadth is 300 miles, though its average breadth is Joliba, pursues a northeasterly course to the neighborhood of not more than 100 miles. This most remarka lake ives Timbuctoo, thence a southeasterly course, passing through a the waters of the Volga, a river which has a course of 2,200 wide opening of the Kong Mountains, and enters the eastern miles, and brings down more than 518,000,000 cubic feet of extremity of the Gulf of Guinea by several mouths. The water every hour. The Ural and many other streams of conlength of the Niger is perhaps about 2,300 miles; above the siderable magnitude are also received by the Caspian ; but its place of its passage through the Kong Mountains it receives level is not changed, though it has no perceptible outlet by the waters of the Chadda, a broad and deep tributary. The which to discharge the water it receives. Niger has been ascended by a steamboat to more than two 286. Lake Aral presents the same phenomenon, and, though hundred miles above the junction of the Chadda, but the ex- not to be compared in extent to the Caspian, receives two large treme unhealthiness of the climate, in the district through rivers, the Sihoon and Amoo or Jihon. The difficulty in exwhich its lower course lies, has contributed to the failure of plaining the nature of these lakes is to account for the conmany attempts made to explore this part of Africa, and to stancy of their level, which might be expected to rise considestablish commercial relations with the inhabitants.

erably, as they are daily receiving so large a body of water. 282. Besides the Niger, the principal rivers upon the west The opinion was entertained that they are connected by some coasts of Africa are the Senegal, the Gambia, the Rio Grande, internal channel with the sea, and it was supported by the fact the Rokelle, the Volta, the Zaire or Congo, the Coanza, and the that the water of both the Caspian and Lake Aral is salt, and

Questions.—278. Extent of the surface drained into the Inland seas? Principal conti- Ques'ions.--The Senegal and the Gambia ? The Gariep? The principal river upon nental rivers of Asia ? Into what seas or lakes do they respectively flow? 279. What is the eastern side ? Other rivers ? 283. Wbere are fresh-water lakes most abundant? In said of the Nile? How formed ? Source of the Nile? In what does it rise? Exploration North America ? In Europe and Asia ? Salt-water lakes ? 284. Into how many olasses of the river? 280. Length ? Basin ? Width of the valley in different parts ? 281. The may lakes be divided ? First class ? Example. Situation of these lakes, etc. ? 285. See. Niger? Its source, direction, and termination ? Length ? How far ascended by a ond class ? Examples. The Caspian? What waters are tributary to 119 256, Lake Aral 8 steamboat? The climate of the district in which its lower course lies ? 282. Other prin- Opinion formerly entertained ? How supported ? How is this hypothesis disproved ? cipal rivers upon the west coasts of Africa ?

How may the constant level be accounted for ? What other lakes belong to this clau ?

[blocks in formation]

contains marine productions; but it has been ascertained that 234 feet. The Caspian Sea, Lake of Tiberias, and the Dead the Caspian is not less than 84 feet below the level of the Black Sea are each below the sea-level,—the first 84 feet. the second Sea, thus completely disproving the hypothesis that they have 600 feet, and the third 1,317 feet.* a connection. It is thought that the phenomena referred to may be accounted for by evaporation and filtration. Besides the Caspian Sea and Lake Aral, there are numerous other bodies of water of this class, the receptacles of the continental rivers. (See table of Continental Rivers, page 31.)

LESSON XI. 287. A third class comprehends all those lakes which receive

LAKES—(CONTINUED). no streams, but give birth to some. Many of these lakes occupy very elevated situations, and are the sources of some of the 290. NORTH AMERICAN LAKES.—The largest lakes in North largest rivers. ,

They are no doubt supplied by springs, the America are Superior, Huron, Michigan, Erie, and Ontario, waters of which rise in their reservoirs until its level is suffi- which are connected with the sea by the channel of the river ciently high to admit a discharge. The lake in Monte Rotondo, St. Lawrence; Winnipeg, which is drained by the river Nelson in Corsica, is one of this class, and is situated 9,000 feet above into the Hudson Bay, and the Athabasca, Great Slave, and the level of the sea.

Great Bear, which empty their waters into streams tributary 288. The fourth class includes all those läkes which both to the Arctic Ocean. receive and discharge water, being by far the most numerous 291. Lake Superior is the largest fresh-water formation on division. They commonly receive the waters of many rivers, the globe, computed to have an area of 40,000 square miles ; and have but one outlet. The origin of such rivers is easily length 420 miles; extreme breadth, 165; height above the explained. Should a hollow present itself in the course of a level of the Atlantic, 623 feet; greatest depth, 1,200 feet. river, it evident that it must be filled to the level of some There is reason to believe, from the appearance of tho shores, part of its banks before the river can proceed, and this would that the waters of this, as well as the other Canadian lakes, produce a lake. But it may happen that there is a general de formerly occupied a much higher level than they reach at presclivity from various parts of a district toward some central ent. The amount of water carried off by its outlet, the river valley, and then the waters of a number of rivers may be of St. Mary, is much less than that received by its tributaries, brought into it, while at the same time the continuation gives from which circumstance it is inferred that the evaporation but one course by which the waters can be discharged. A from its surface must be very great. description of some of the largest lakes of this class will be 292. Lake Huron, remarkable for its brilliant transparency, given in the next lesson.

has an area of 25,000 square miles. It is about 240 miles in 289. Most lakes occur at varying elevations above the level length, from 180 to 220 in breadth, and is 591 feet above the of the sea, while some are much below it. ; The highest known level of the sea. The outline of this lake is very irregular, and lake in the world is Sir-i-kol, in Asia. It is the source of the its shores are described as consisting of clay cliffs, rolled stones,

abrupt rocks, and wooded steeps. The greatest depth of Lake Huron is found to be nowhere more than 450 feet. Lake Michigan, which lies wholly within the United States, is connected with Lako Huron by means of the navigablo channel Mackinaw. It is about 300 miles long, and has an area of about 25,000 square

miles. 293. Lake Eric has an of about 11,000 square miles; its surface is 565 feet above the sea.

This lake is said to be the only Amoo River, and is 15,630 feet abore the level of the ocean. one in the whole Canadian chain in which there is any percepLake Titicaca, in Bolivia, bas an elevation of 12,785 feet; tible current, a circumstance which is supposed to be attributable Tzana or Dembea, in Abyssinia, 6,076 feet; Lake Baikal, in to its comparative shallowness, its average depth being not more Asia, 1,793 feet ; Constance, 1,299 feet; Geneva, 1,229 feet; than 60 or 80 feet. The current of Lake Erie, which runs alGreat Salt Lake, in Utah Territory, 4,200 feet; Superior, 623 ways in one direction, combined with the great prevalence feet; Huron and Michigan, 591 feet; Erie, 565 feet; Ontario, of westerly winds, and the occurrence of sunken reefs and

[graphic]

area

LAKE TITICACA.

Questions.-291. Give particulars of Lako Superior. Change of level ? 292. Givo particulars of Lake Huron, Lake Michigan. 293. Lake Eric. What is said of its cur rent? Its navigability ?

Questions.-287. Third class ? What is said of many of the lakes of this class? How supplied ? Monte Rotondo ? 258. Fourth class ? How is the origin of such lakes explained ? 289. Varying elevations and depressions of lakes ? Highest known lake, its elevation, etc. ? Give the elevations of the other lakes mentioned. State the depressions of the Caspian, Lake of Tiberias, and the Dead Sea. 290. Which aro the largest lakes in North America, and how drained ?

* According to the measurement made by Lieutenant Lynch, in 1943, the exact depres sion of the Dead Sea below the Mediterranean was found to be 1,816.7 feet.

rocky banks, form serious obstacles to the safe and easy naviga- coast of the Pacific is only eleven miles; it is drained by the tion of this lake. The shallowness of the water of Lake Erie San Juan, which flows into the Caribbean Sea. likewise causes it to be more readily and more permanently 298. South AMERICAN LAKES.—South America has few affected by frost, so that its navigation is usually obstructed by lakes of any great extent. The largest is Lake Titicaca (about ice for some weeks every winter, while that of the other lakes 3,800 square miles), situated on a plateau of that name, at an continues open and unimpeded.

elevation of 12,785 feet, and surrounded by some of the highest 294. Lake Ontario has a computed area of 10,000 square summits of the Andes. The water of Lake Titicaca is fresh; a miles, 234 feet above the sea-level, and 331 feet below the level river called the Desaguadero, which leaves its southern exof Lake Erie. Its depth is said to be very great, and it is tremity, flows into the smaller lake (or marsh) of Aullagas, or navigable throughout its whole extent for the largest ships. Its Uros, which lies at 490 feet lower level, and the water of which outlet is a spacious channel studded with islands, collectively is salt. denominated the Thousand Isles, but no less than 1,692 have 299. Lake Maracaybo (5,000 square miles), near the coast been actually counted.

of the Caribbean Sea, is connected by a narrow strait with the 295. Lake Champlain about 500 square miles) belongs to Gulf of Maracaybo, and has brackish water. The Lake dos the same basin as the great lakes above described, and is con- Patos and Lake Mirim are on the southeast coast of Brazil. nected with the St. Lawrence by the river Richelieu. Lake George, noted for its picturesque scenery, and for the transparency of its waters, is situated west of the southern extremity

LESSON XII.

[graphic]

LAKES (CONTINUED). 300. EUROPEAN LAKES.— There are two principal lake-regions in Europe, one lying around the Baltic, and situated within its basin; and the other embracing the Alpine system of mountains. The lakes situated in the former of these regions possess, in general, greater magnitude, while the latter are distinguished by their great elevation above the sea, and by the grandeur of the scenery among which they lie.

301. The following tables give the dimensions of the principal European'lakes, together with their elevation and greatest depth, where these particulars have been ascertained.

LAKES SITUATED ROUND THE BALTIC.

Area in sq. miles. Height. Depth.

ITNEY-LOCELYN-AMIR.

LAKE GEORGE.

[blocks in formation]

of Lake Champlain, with which it is connected by a short stream. It is about 30 miles long, and from one to two miles broad.

296. The Great Salt Lake (about 2,600 square miles), situated in the great basin between the Rocky Mountains and the Sierra Nevada (111), is about 70 miles in length, from 30 to 35 miles in breadth, and is about 4,200 feet above the level of the sea. Its waters are saturated with common salt, and when the lake is low, considerable quantities of this substance are precipitated to the bottom of the lake, or, rather, are there crystallized. No living animal can exist in this lake. It receives the waters of the Bear, Weber, and other rivers, but, like other lakes in this region, has no connection with the ocean.

297. Upon the Mexican plateau is the large lake of Chapala (about 650 square miles), which is discharged into the Pacific by the river Santiago. Lake Nicaragua (about 3,500 square miles), in Central America, lies at an elevation of about 128 feet above the sea. The distance between its western shore and the

[blocks in formation]

Questions.-294. Give particulars of Lake Ontario. The Thousand Isles. 295. Lake Champlain. Lake George. 296. Great Salt Lake. What are its waters ? 297. Give particulars of Lake (hapala. Lake Nicaragua. 293. What is said of South America ? Lake TitiLuca ? 299. Lake Maracaybo? Other lakes? 300. How many lake-regions are there in Europe, and where are they respectively situated ? How are the lakes of each division characterized ? 801. What is the area of Lake Ladoga? or Onega?

Questions.-Of other lakes in Russia ? Give particulars of Lake Wener. Of other lakes in Sweden. Or Geneva. or other lakes in Switerland. Of Lake Maggiore. or other lakes in Italy.

. The waters of Lake Enara, however, communicate with the Arctic Ocean, not with

Itic.

[blocks in formation]

302. Lakes are very numerous in Scotland, especially in the from this, at a lower elevation, are Lake Little Luta Nzige middle and northern parts. They are mostly long and narrow (unexplored), and Lake Tanganyika or Ujiji. Among other bodies of water, occupying the deep hollows within the elevated noted African lakes are Tzana or Dembea, in Abyssinia, and mountain valleys. The largest lake in Scotland, and also in Nyanja or Nyassi, and Shirva, in or near the borders of MoGreat Britain, is Loch Lomond (45 square miles), which is 24 zambique. miles in length, and 7 miles in its greatest breadth.

303. Of the lakes in Ireland the largest is Lough Neagh (150 square miles), situated in the north of Ireland, and the Lakes

LESSON XIII.

[graphic]

THE OCEAN.

308. The vast body of water which surrounds the land and penetrates its coast is comprehended under the general name of the ocean. For convenience sake it is divided into five portions, named, respectively, the Arctic, Atlantic, Indian, Pacific, and Antarctic oceans. These, with their branches, are as follows:

I.
Extends from the northern ) Baffin Bay.

shores of America, Europe, White Sea. ARCTIC OCEAN

Asia, and the arctic circle Gulf of Kara. around the north pole ..... Gulf of Obi.

Branches.

II.

LAKE KILLARNEY.

[blocks in formation]

of Killarney (three in number), noted for their beautiful scenery, in the south.

304. Asiatic LAKES.—The largest fresh-water lake in Asia is Lake Baikal, situated among the northern offsets of the Altai mountain-system: it has an area of about 15,000 square miles, and lies at an elevation of 1,793 feet above the level of the sea. Its water is fresh, and abounds in fish. It is annually frozen over for a period of five or six months, and may be traversed on sledges.

305. Among the smaller lakes of Asia are Balkash, Upsa-nor, Zaizang, Issi Kol, Bosteng, Lop, Koko-nor, Bouka-nor, and Tengri-nor—all on or adjacent to the high plateaus in the interior of the continent; Tung-ting and Poyang, in China; Zurrah and Bakhtegan (both salt), on the plateau of Afghanistan and Persia; Ooroomiah, Van, and Goukcha (the two former of which are salt), on the Armenian table-land; the salt lake of Koch-hissar, in Asia Minor; with Lake Tiberias and the Dead Sea in Palestine.

306. AFRICAN LAKES. The largest body of inland water known in Africa, until recently, was Lake Tsad. It lies in the central part of the continent, and is several thousand square miles in area; but its waters are very shallow. It is not known to have an outlet, but is fresh and clear, and probably has a channel of discharge like other fresh-water lakes.

307. Recent explorations in the southeast of Africa have made known the existence of several large lakes, the most extensive of which is Lake Victoria Nyanza or Ukerewe, the long-sought source of the Nile. Its area is not yet determined, but is believed to considerably exceed that of Lake Tsad. Its height is 3,553 feet above the level of the sea. Not far

[blocks in formation]

V.

Extends from the antarctic
ANTARCTIC OCEAN...
circle around the south pole.

}
309. The Arctic Ocean has been but partially explored.
Various efforts have been made to reach its higher latitudes,
but, up to this time, they have proved unsuccessful, in con-
sequence of the impenetrable fields of ice wbich are met with,
and the impossibility of remaining in those regions with safety
for a great length of time. During the winter months the waters
of the Arctic Ocean are covered with ice, which in summer is
broken

up and drifted into lower latitudes, where it is dissolved.

Questions.—302. What is said of the lakes in Scotland ? Loch Lomond ? 303. Lakes in Ireland ? 304. Give particulars of Lake Baikal. 305. What other Asiatic lakes are inentioned ? 806 Give particulars of Lake Tsau. 307. Or Lake Victoria Nyanza. Lakes near it? Other noted African lakes ?

Questions.—308. Under what general name is the vast body of water which surrounds tho land comprehended? How is it divided ? Describe the situation, and mention the principal bran hes of the Arctic Ocean, Atlantic, Pacific, Indian, Antarctio. 309. What is said of the Arctic Ocean? Why have the efforts made to reach its higher latitudes been unsuccessful?

« 前へ次へ »