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The following table exhibits the principal islands throughout the globe, with their extent.

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3. Capes, Peninsulas, &c. A part of the land running out into the sea, and joined to the mainland only by a narrow neck is called a peninsula ; projections of land of less extent, reaching but a little way into the sea are called capes, headlands, promontories, or points. A narrow neck of land joining larger masses is called an isthmus.

4. Oceans. There is in fact one continuous mass of water, called the ocean, surrounding the land which rises above its level in continents and islands ; but for convenience sake different parts of it have distinct names given to them, as appears by the following table :

I. The great Southeastern Basin, the waters of which cover nearly half the globe, includes :

1. The Pacific Ocean 11,000 miles in length from east to west, and 8,000 in breadth, occupying a superficial space rather larger than the whole mass of the dry land. It extends from Behring's 'Straits on the north, to a line drawn from Cape Horn to Van Diemen's Land on the south ; and from America on the East, to Asia, Malaysia, and Australia on the west. In consequence of the wide expanse of its surface it is remarkably exempt from storms, except near its mountainous shores, and hence its name. It is often also called the South Sea ;

11. The Indian Ocean, lying between Africa on the west, and Malaysia, and Australia on the east, and between Asia on the north, and a line drawn from the Cape of Good Hope to Van Diemen's Land on the south, is about 4,500 miles in length and breadth ; it covers a surface of about 17,000,000 square miles;

1. The Southern or Antarctic Ocean surrounds the south pole, lying to the south of a line drawn quite round the globe from Cape Horn, along the southern extremity of New Zealand,

miles ;

Van Dieman's Land, and Africa, back to the point of starting. It embraces an area of 30,000,000 square miles. It is generally covered with floating ice as far north as 60° south latitude, and in higher latitudes appears to be blocked up by an impenetrable barrier of fixed ice.

II. The Western Basin forms a channel between the eastern and western continents, and washes their northern shores. It includes :

1. The Atlantic Ocean stretching from the Southern Ocean to the Arctic circle ; it is about 8,500 miles in length, varying much in breadth, and it covers an area of 25,000,000 square

11. The Arctic Ocean surrounding the north pole ; it is in part covered with impenetrable fields of perpetual ice, and it contains large masses of land of unknown extent. It is often called the Icy or Frozen Ocean or Polar Sea ;

5. Uses of the Ocean. Although it presents to the eye only the image of a watery waste, the ocean sustains an important part in the economy of nature. It is the fountain of those vapors which replenish the rivers and lakes, and dispense fertility to the soil. By its action on the atmosphere it tempers the extremes of heat and cold. It affords an inexhaustible supply of food and of salt, a substance hardly less important. As the great highway of commerce it connects the most distant parts of the globe, affording facilities of intercourse to nations the most remote from each other.

6. Seas, Gulfs, and Bays. When the ocean penetrates into the land forming a large expanse of water, this inland portion of the ocean is usually termed a sea ; such a body of water of less extent is generally called a gulf or bay ; but these three terms are often confounded.

The following are the principal bays : Baffin's, Hudson's, James's, Fundy, Passamaquoddy, Machias, Penobscot, Casco, Massachusetts, Buzzard's, Narragansett, Delaware, Chesapeake, Campeachy, Honduras, Bristol, All Saints, Cardigan, Donegal, Galway, Biscay, Bengal, Walwich, Fable, False, Angola, Natal, Saldanha, and Botany.

The following are the principal gulfs : St. Lawrence, Mexico, Darien, California, Panama, Guayaquil, St. George, Bothnia, Finland, Riga, Genoa, Naples, Tarento, Venice, Salonica, Persian, Ormus, Siam, Tonquin, Corea, Obi, Guinea.

The principal seas are the following : Chinese, Carribean, Mediterranean, Okhotsk, Celebes and Corea, Black, North, Red, Baltic, White, Azof, Marmora, and Irish.

7. Strait, Sound, &c. A narrow passage of water leading from one sea or gulf to another, is called a strait ; a wider passage between two large bodies of water is called a channel or sound.

The principal channels and straits are the following : Davis's, Hudson's, Belle Isle, Michillimackinac, Behring's, Magellan, Skager Rack, Cattegat, Dover, Gibraltar, Bonifacio, Messina, Dardanelles, Constantinople, English, St. George's, North, Babelmandel, Ormus, Mozambique, Sunda, Malacca, Endeavor, Bass's, Dampier's, and Cook’s.

The following are the principal sounds : Long Island, Albemarle, Pamlico, Prince William's, Queen Charlotte's, and Nootka.

8. Harbors, Roadsteads, &c. Small bays or arms of the sea, completely landlocked, or so much so as to protect ships lying in them from the winds and the sea-swell

, are called ports, harbors, or havens ; more open arms of the sea, which afford good anchoring ground, are called roads or roadsteads. A good harbor must be deep, capacious, and safe.

9. Depth of the Ocean. The bottom of the sea appears to have inequalities similar to the surface of the dry land, and the depth of the water is, therefore, various. There are vast spaces where no bottom has been found, and if it is true that the depth of the sea bears any analogy to the elevations of the dry land, it would be in some places from 20,000 to 26,000 feet; the greatest depth ever sounded is 7,200 feet.

10. Tides. Tides are regular periodical oscillations in the waters of the ocean, which are caused by the attraction of the sun and moon, and which take place twice every twenty-four hours. In the open sea they are at their height three hours after the moon has passed the meridian of the place, and the meridian opposite. Their greatest elevations take place in narrow seas, where the action of the sun and moon is assisted by winds, currents, the position of the coast, &c. The highest tides known are in the Bay of Fundy, where the flood rises to the height of 70 feet.

11. Currents. Beside the motions produced by the tide, it has been found that there are permanent oceanic currents, always setting in the same direction. There is one called the polar current which sets from each pole towards the equator, as appears from the masses of floating ice, constantly moving in that direction. Another current, called the tropical current, sets, within the tropics, from east to west ; so that vessels coming from Europe to America, descend to the latitude of the Canaries, where they are carried rapidly westward, and in going from America across the Pacific to Asia, a similar effect is observed. The Gulf Stream is one of the most remarkable and best known of the oceanic currents.

12. Whirlpools. When two opposite currents of about equal force meet one another, they sometimes, especially in narrow channels, turn upon a centre and assume a spiral form, giving rise to whirlpools. Sometimes the most violent of these, when agitated by tides or winds, become dangerous to navigators.

13. Saltness of the Sea. The waters of the sea hold in solution several salts, among which are common salt or muriate of soda, Epsom salt or sulphate of magnesia, and Glauber's salt or sulphate of soda. The saltness of the sea varies in

different places, but is generally less toWhirlpool

wards the poles than near the tropics, and in inland seas or bays than in the open ocean. . In some places springs of fresh water rise up in the midst of the sea. The bitterness of sea-water is supposed to be owing to the decomposed animal matter which it contains. It is easier to perceive the great advantages arising from the saltness of sea-water than to discover its origin. Without this saltness and without the agitation in which its waves are constantly kept, the ocean would become tainted. It is remarkable, that the saltness

of the sea is less toward the poles than under the equator. 14. Color of the Sea. The green and yellow shades of the ocean arise from marine plants. The sparkling of the sea at night presents an imposing spectacle. A vessel, while ploughing her way through the billows, often appears to mark out a furrow of fire ; sometimes every stroke of the oar of a boat, emits a light either brilliant and dazzling, or tranquil and pearly. This wonderful phenomenon is supposed to be produced, at least in part, by multitudes of small phosphorescent animals that live in the water.

15. Temperature of the Ocean. The temperature of the sea changes much less suddenly than that of the atmosphere, and it is by no means subject to such extremes of heat and cold as the latter.

IV. SURFACE OF THE LAND. 1. Inequalities of Surface. The inequalities of the earth's surface arising from mountains and valleys, may be likened to the roughnesses on the rind of an orange compared with its general mass. The highest mountain known does not exceed five miles in perpendicular height; this is only one 1600th part of the earth's diameter, and on a globe of 16 inches in diameter, such

a mountain would be represented by a protuberance of one hundredth part of an inch, which is about the thickness of drawing-paper. The deepest mine does not penetrate half a mile below the surface ; and a scratch or pin-hole duly representing it on the surface of such a globe, would not be perceptible without a magnifier. The greatest depth of the sea does not probably much exceed the greatest elevation of the continents, and the ocean would be represented by a mere film of liquid, such as in our model would be left by a brush dipped in color, and drawn over those parts intended to represent the sea.

2. Mountains. The greatest elevations of the earth's surface are called mountains ; elevations of

an inferior height are called hills. Mountains are View of the Alps.

sometimes completely insulated, but they are more

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commonly disposed in chains; a chain is a series of mountains, the bases of which are continuous. . Several chains are often connected with each other, forming a group ; and several groups in the same manner form a system.

The height of mountains is their elevation above the level of the sea, and as the bases are often situated upon elevated plains, the apparent height of the mountainous peaks is much less than their absolute height. Cols or necks are depressions in mountainous chains affording a passage from one declivity of the ridge to the opposite ; they are sometimes called gates, gaps, or passes.

Heights of Principal Mountains.
Europe.

Asia.
Feet.

America.
Feet. Dhawalagiri (Himala), 26,862

Feet. Mont Blanc (Alps), 15,781 Jamautri 25,500 Sorata (Bolivia),

25,000 Mont Rosa 15,555 Elburz (Caucasus), 18,500 Illimani,

24,450 Jungfrau 13,720 Ararat (Armenia), 17,266 Chimborazo (Peru),

21,440 Mont Perdu (Pyrenees), 11,283 Demavend (Persia), 14,700 Cotopaxi (Peru),

18,890 Mulahacen (Sierra Nevada), 11,673 Lebanon (Syria),

9,520 Mt. Hooker (British America), 20,000 Ætna (Sicily),

10,963
Africa.

Popocatepetl (Mexico), 17,716 Parnassus (Greece), 8,000 Geesh (Abyssinia), 15,000 Orizaba

17,370 Ben Macdiu (Scotland) 4,418 Teneriffe Peak (Canaries), 12,236 Mt. St. Elias

17,670 Snowdon (Wales),

3,571 Lupata (South Africa), 12,000 Long's Peak (United States), 13,430 Helvelyn (England), 3,055 Atlas (Morocco),

11,400 Black Mountain (N. Carolina), 6,426 Oceanica.

Mt. Washington (N. Hampshire) 6,428
Mouna Koah (Sandwich I.), 18,400
Ophir (Sumatra),

13,842 3. Forms and Use of Mountains. Mountains, in their exterior forms, exhibit some varieties, which strike the most inattentive observer. The highest mountains most frequently present a surface of naked rock. In some places they shoot up in the form of enormous crystals with sharp angles. Sometimes there appears an immense, steep, and abrupt surface, which seems to lay open to view the bowels of the mountain itself

. These appearances are described under the names of needles, peaks, &c. There are other mountains, the tops of which present circular outlines, which give them an air of tranquillity. The mountains of New England and the Appalachian chain generally, are of this character. Some mountains rise in majestic and regular gradations, like a vast amphitheatre ; others present a large mass cut perpendicularly in the form of an altar, like the Table Mountain at the Cape of Good Hope. There are mountains in China which resemble the heads of dragons, tigers, and bears. In other places there are labyrinths of rocks, which rise in the form of pillars. In the southeastern part of France, there is a mountain in a single mass in the form of a large nine-pin. In another part of France, there are mountains which are described as resembling the oldfashioned frizzled wigs. In short, the varieties in the form of mountains, as described by travellers, seem to be almost infinite. Some of them are highly picturesque and beautiful, and fill the mind of the beholder with pleasing emotions. Others are lofty, rugged, and sublime, and awaken feelings of awe and astonishment.

The utility of mountains is very great. They attract the clouds and vapors, which become condensed by cold, and fall in the shape of snow and rain, thus giving birth to innumerable streams, which descend and spread fertility and beauty over the surface of the earth.

4. Volcanoes. Those mountains which send forth from their summits or sides, flame, smoke, ashes, and streams of melted matter or lava, are called volcanoes.

The deep hollow from which these substances are emitted is called a crater. Some elevations merely discharge mud or air, and have received the name of air or mud volcanoes. Many mountains present appear

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that at some former time they must have been outlets of fire, although they have long ceased to have any volcanic

action ; these are called extinct Volcanic Mountain ; Vesuvius.

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From most active volcanoes, smoke issues more or less constantly ; but the eruptions, which are discharges of stones, ashes, and lava, with columns of flame, violent explosions, and concussions of the earth, happen at irregular, and sometimes at long intervals. There are about 500 volcanoes upon the surface of the earth.

A vast volcanic zone surrounds Greece, Italy, Germany and France. Several islands in the

. Grecian Archipelago, have been raised from the sea by volcanic convulsions. Etna has burnt for 3300 years, and is surrounded by extinguished volcanoes, which appear still more ancient. The Lipari islands seem to be formed chiefly of the lava and other substances which have been thrown from their volcanoes. Other parts of Europe exhibit traces of volcanoes now extinguished. Iceland has several volcanoes, of which Hecla is the most remarkable. The very bottom of the ocean in the neighborhood of this island, is sometimes convulsed, and the waves often heave up whole fields of pumice stones.

The origin of volcanoes is a Volcanic Island in the Sea.

subject upon which scientific men have entertained different opinions ;. the most rational of these ascribe them to the burning of bitumen, fossil-wood, pit-coal, &c. set on fire by the spontaneous combustion of pyrites, a metallic substance formed of iron and sulphur.

The eruption of a volcano is a most frightful and majestic phenomenon. The first signs which announce that the invisible combat of the elements has already commenced, are violent movements, which shake the earth afar off, prolonged bellowings and subterranean thunders, which roll in the sides of the agitated mountain. Soon the smoke ascends in the shape of a black column. This is dispersed by the winds, and formed into trains of clouds. A volume of flame rises above the clouds, seeming like a pillar of fire, which rests upon the ground and threatens to set the skies in a blaze. A black smoke environs it, and from time to time intercepts the dazzling brightness. Lightnings appear to flash from the midst of the burning mass. On a sudden, the vast pillar of fire seems to fall back into the crater, and its fearful splendor is succeeded by profound darkness. But now ashes, dross, and burning stones are projected in diverging lines, and fall around the mouth of the volcano. Enormous fragments of rocks appear to be heaved against the skies. A torrent of water is often thrown out with impetuosity, and rolls hissing over the inflamed rocks. There is then raised from the bottom of the crater a liquid mass of burning lava, which fills the cavity and reaches to the very top of the opening. This is the prelude to real disasters. The liquid matter overflows, and runs down the sides of the mountain. It advances like a large and impetuous river, destroys whatever it meets within its course, flows over those obstacles which it cannot overturn, passes along the ramparts of shaken cities, invades a space of country of several leagues in extent, and transforms, in a short time, flourishing fields into a burning plain.

5. Earthquakes. Earthquakes are supposed to be intimately connected with volcanoes, and usually take place in volcanic countries. There have been frequent earthquakes near the borders of the Mediterranean Sea, and around the Gulf of Mexico. These dreadful phenomena often change the surface of a country, so that it is difficult to recognise it. During the convulsion, enormous gaps in the earth appear to disclose to the living the empire of the dead; these fissures emit blue Names and deadly vapors. Vineyards descend from their heights, and settle in the midst of fields of corn ; farms and gardens quit their places and become attached to distant villages ; towns are shaken down, villages are swallowed up, mountains sink into

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