The Circle of Knowledge: A Classified, Simplified, Visualized Book of Answers

Part 15

Chapter 152,403 wordsPublic domain

FRESHWATER AND SALT LAKES

Lakes are of different kinds. Some are mere tanks which receive the first outpourings of springs, others consist of basins or reservoirs which occur in the line of a river’s course; some consist of basins or cavities, into which rivers flow, but which, on account of their depression or their mountainous cincture have no outlets; lakes are also formed in the craters of extinct volcanoes; and some lakes are periodic, or subject to have their basins alternately empty and full of water.

MOUNTAIN LAKES, which are valleys or chasms filled by streams, are long and narrow, rarely of extensive area, but often of great depth. Examples of this class are found in Lakes Champlain and George, among the Appalachian Mountains; Lakes Constance and Geneva, on the northern side of the Alps; and Lake Maggiore and Lake Como, on the south side; all of which are renowned for the loveliness of their shores, or the grandeur of the surrounding mountain scenery.

Lake Maggiore, which is hardly three miles wide, is, according to Italian engineers, 2,623 feet deep--more than double the depth of Lake Superior--its basin reaching 1,936 feet below the sea level.

The forms of mountain lakes are very irregular, for the water often covers several contiguous and connected valleys. This is the case in Lake Como, which has two long arms; and Lakes Lucerne and Lugano, each of which fills four distinct valleys, meeting one another nearly at right angles.

LAKES IN PLAINS. The lake basins in plains and plateaus are, usually, simple depressions in a comparatively uniform surface. The lakes are, therefore, often of great size, broad in proportion to their length, but of little depth compared with their area.

The largest lakes of the globe--the Caspian and Aral seas, and the great North American and African lakes--and the largest in Europe and South America, all belong to this class. Their vast expanse, together with the tameness of their shores, deprives them of the picturesque beauty of mountain lakes.

CHARACTERISTICS OF SALT LAKES. Numerous lakes in the interior of the continents, though receiving affluents, have no outlet. Their waters are chiefly lost by evaporation, though some portion may be absorbed by the sandy soil.

The surfaces of the continents having been the beds of the primeval oceans, the presence of salt in the soil is a natural consequence.

FAMOUS SALT LAKES. The Great Salt Lake of Utah, in the Great American Basin, is one of the finest examples of its class. The Caspian and Aral seas, at the bottom of the vast depression between Europe and Asia, are the most extensive salt lakes. The former has about four times the area of Lake Superior; and the latter is a little larger than Lake Michigan.

The Caspian, though receiving the Volga, the largest river of Europe, evaporates so much water that its surface is about 83 feet lower than that of the Mediterranean, varying with the seasons. Many lakes in its neighborhood disappear entirely in the heat and drought of summer, leaving their beds covered with a crust of pure white crystalline salt.

THE REMARKABLE DEAD SEA, in Syria, is a lake in which the salt has accumulated until the water is converted into a heavy brine. It may be the remnant of an ancient sea of much greater extent, which has been gradually reduced in size by the excess of evaporation over the supply of water in its basin.

This celebrated body of water lies in the deepest part of a long chasm or valley, which is sunk not less than 4,000 feet below the level of the surrounding country. The surface of the lake is 1,286 feet, and its bottom 2,500 feet, below the level of the Mediterranean.

Its feeder, the river Jordan, flows almost throughout its entire course below the level of the sea, the only known instance of the kind. The beautiful lake of Tiberias, the scene of so many of the miracles of Jesus, which is but an expansion of the Jordan in its upper course, is about 650 feet below the surface of the Mediterranean.

HOW THE LAKES ARE DISTRIBUTED OVER THE GLOBE

Lakes are most numerous in the central and northern portions of Asia, Europe and North America. The southern continents, except Africa, have comparatively few.

ASIA is pre-eminently the continent of salt lakes. They occur in countless numbers, both in the steppes north of the Caspian and Aral, and in all the interior plateaus. Lakes of fresh water are also found among the Altai Mountains and adjacent chains. Lake Baikal, one of these, is the largest mountain lake known, being nearly 500 miles long.

EUROPE. The most characteristic and celebrated lakes are those which adorn the Alps of Switzerland and Scandinavia, and the less lofty mountain chains of the British Isles. But the largest lakes are found in the low lands and slight swells which surround the Baltic Sea, in western Russia and Sweden. Lakes Ladoga and Onega in Russia, and Wener and Wetter in Sweden, are the largest in Europe.

NORTH AMERICA is peculiarly rich in great lakes. No continent presents a more remarkable series than that which stretches from northwest to southeast, through the central plains, along the line of contact of the oldest geological formations of the continent. This series includes Great Bear and Great Slave lakes, Athabasca and Winnipeg, and the five great lakes of the St. Lawrence, with many of less area.

Innumerable small lakes are scattered throughout the middle portions of the central plain, and the northern and less regular part of the Appalachian mountain region; but south of the parallel of Lake Erie there is an almost entire absence of lakes, whether large or small.

PRINCIPAL SALT-WATER LAKES OF THE WORLD

PRINCIPAL FRESH-WATER LAKES OF THE WORLD

AFRICA. The great plateau lakes are typical of the continent. The Victoria Nyanza and Albert Nyanza, feeding the White Nile; Tanganyika, whose outlet is unknown; Tzana, at the head of the Blue Nile; and Lake Nyassa, in the Zambezi basin, all rest on the high plateaus of Central Africa. Lake Tchad alone, among large African lakes, is surrounded by low plains.

WATERFALLS AND RAPIDS. The variations in the slope of a river-bed, arising from unequal erosion, or from the original irregularities in the surface, give rise to rapids and falls.

The first occur where an increased slope causes the stream to flow with more than its average velocity. The second are caused by nearly perpendicular rocky walls, down which the foaming water descends in picturesque cascades, or imposing cataracts.

The famous “Cataracts of the Nile” are merely rapids which impede but do not entirely obstruct, the navigation as cataracts must. The so-called Falls of St. Anthony, in the upper Mississippi, and the rapids of the St. Lawrence, above Montreal, are among the finest rapids in American rivers.

The highest falls are in the upper course of rivers, in mountainous regions; the greatest and most imposing, in their middle course.

The Niagara Falls exhibit a most important industrial utilization of water power. The Falls of St. Anthony in the Mississippi, the Falls of Foyers in Scotland, the Rhine falls, the Rhone falls of Bellegarde, and the innumerable waterfalls of Scandinavia, Switzerland, and similar mountainous lands, are all utilized in this way. It has been proposed to convey power generated at the Victoria falls of the Zambezi to the Rand goldfield of the Transvaal, and a scheme for this is now being prepared.

=FAMOUS WATERFALLS OF THE WORLD=

NAME LOCATION HEIGHT (FEET) =Bridal Veil= California 900 =Foyers= Great Britain 205 =Gastein Falls= Austria 469 =Gavarnie= Pyrenees 1,400 =Genesee= New York 95 =Grand Falls= Labrador 2,000 =Great Falls= Montana 500 =Hay River= Alaska 200 =Kaieteur Falls= Guiana 740 =Krimmler Falls= Austria 1,300 =Kukenam Fall= Guiana 1,500 =Maanelvan= Norway 940 =Minnehaha= Minnesota 50 =Missouri= Montana 90 =Montmorenci= Quebec 265 =Multnomah= Oregon 850 =Murchison= Africa 120 =Nevada Falls= California 600 =Niagara= New York 165 =Oroco Falls= Monte Rosa 2,400 =Rjukanfos= Norway 804 =Roraima Fall= Guiana 2,000 =Rukaufos= Norway 513 =St. Anthony= Minnesota 80 =Schaffhausen= Switzerland 100 =Seven Falls= Colorado 266 =Shoshone= Idaho 210 =Skykjefos= Norway 700 =Snoqualmie= Washington 268 =Staubbach= Switzerland 1,000 =Stirling= New Zealand 500 =Sutherland= New Zealand 1,904 =Takkakaw= British Columbia 1,200 =Tequendama= Colombia 475 =Tessa Falls= Austria 541 =Twin= Idaho 180 =Velino Falls= Italy 591 =Vermafos= Norway 984 =Vettisfos= Norway 950 =Victoria Falls= Zambezi 400 =Voringsfos= Norway 600 =Yellowstone (upper)= Montana 110 =Yellowstone (lower)= Montana 310 =Yguazu or Iguazu= Brazil 210 =Yosemite (upper)= California 1,436 =Yosemite (middle)= California 626 =Yosemite (lower)= California 400

THE OCEANS OF THE WORLD AND THEIR MYSTERIES

The Oceans consist of one great fluid mass, and in extent covers three times the area of the dry land. There is also about three times as much land to the north of the equator as there is to the south of it. Though the waters of the ocean surround the land on every side, yet they are broken up into certain areas by the arrangement of the land portions, and to these various parts we give particular names.

The Atlantic Ocean, lying between the western shores of Europe and Africa and the east coast of America.

The Pacific Ocean, lying between the west coast of America and the east coast of Asia.

The Indian Ocean, lying between the south of Asia and the Antarctic circle.

The Arctic Ocean, lying within the Arctic circle.

The Antarctic Ocean, lying within the Antarctic circle.

VAST EXTENT OF THE OCEANS

THE ATLANTIC is the most branching of the oceans, and is especially distinguished by the number and great size of its inland seas. Two of these, the Mediterranean Sea and the Gulf of Mexico, lie in the warm regions; and two, Hudson Bay and the Baltic Sea, in colder latitudes.

The broader seas are represented by the Caribbean Sea, within the tropics and the Gulf of St. Lawrence and the North Sea in temperate latitudes. The Gulf of Guinea, and the Bay of Biscay, are examples of the more shallow coast waters.

THE PACIFIC is particularly rich in vast border seas, a continuous series of which lines the Asiatic and Australian coasts. Among these are the Behring Sea, enclosed by the peninsula of Alaska and the Aleutian Islands; Okhotsk Sea, enclosed by Kamchatka and the Kurile Islands; the Sea of Japan, and the North and South China seas; and the Arafura, Coral, and New Zealand seas, on the Australian Coast.

Only two inland seas of considerable size--the Gulf of California in North America, and the Yellow Sea in Asia--mark this entire basin.

THE INDIAN OCEAN is characterized by gulfs, two of which form the entire extension of the basin; namely, the Gulf of Bengal, and the Arabian Sea. It has also two inland seas of considerable extent, the Red Sea and the Persian Gulf, isolating the peninsula of Arabia from the adjacent continents; but border seas are wholly wanting in the Indian Ocean.

THE ARCTIC OCEAN is a partially enclosed sea, which a comparatively inconsiderable rise of the sea-bottom would convert into a true Mediterranean. Three openings connect it with the Pacific and Atlantic Oceans, namely, Behring Straight (narrow and shallow), Davis Straight, and the broad expanse of water lying between Norway and Greenland. Of these, the last is by far the most important, for through it the warm waters of the Gulf Stream find access to the Polar basin, and keep the sea free from ice throughout the year. This current is supposed to flow feebly along the coast of Siberia, until, deflected by the land, it becomes merged in the cold counter-currents which, passing along the eastern coasts of Greenland and Labrador, carry immense masses of ice into the Atlantic.