12

Arabia, Spain, and California, at the southwest, are very simple in form, and have no such islands; Hindostan, Italy, and the long isthmus of Central America correspond in position.

Questions (I.)-1. Which has the greater surface, the Old World or the New World? How many times as much? What is the line of direction of the Old World! Of the New World?—2. Of what does each of these land-masses consist? Which part is the larger? How is Africa joined to Asia? North America to South America?— 3. In what are South America and Africa alike?-4. In what direction does each continent widen? In what direction does it narrow?-5. In what direction do nearly all the great peninsulas point?-6. Name the three northern continents. What is their form? Name the three southern continents. What is their form?-7. How do the coasts of the northern continents differ from those of the southern continents?

(II.)-2. Why are the two isthmuses of great commercial importance?-3. To what may the similarity of South America and Africa be compared?-5. Which continents have nearly all the great peninsulas? In what two directions do the principal shorelines, mountain ranges, and island chains lie?-7. What points of resemblance have the three northern continents?

surface as the New World.

1. The Old World has more than twice as much Its line of direction, or line of greatest length, is from northeast to southwest. The New World extends from northwest to southeast.

2. Each of these great land-masses consists of two parts, the larger being to the north. Africa is joined to Asia by the narrow Isthmus of Suez, and South America to North America by the Isthmus of Panama.

These two isthmuses are of great commercial importance, because the principal routes connecting the commerce of the great oceans pass across them.

3. The southern continents, South America and Africa, are much alike in shape and direction.

Their similarity is somewhat like that of the two hands.

4. Each continent widens toward the north and narrows

to a point at the south.

5. Nearly all the great peninsulas point in a southerly direction.

They project from the three northern continents. The principal shore-lines of the continents, nearly all of the great mountain ranges, and most of the great chains of islands lie in a southeasterly or southwesterly direction.

6. The three northern continents, North America, Europe, and Asia, are irregular in form. The three southern continents are South America, Africa, and Australia; the first two are peninsular in form.

7. The coasts of the northern continents, and particularly those of Europe, are much broken by inland seas. Those of the southern continents are nearly unbroken by peninsulas or by arms of the ocean.

Each northern continent has three great peninsulas projecting from its southern border. These peninsulas are curiously alike in some particulars: Indo-China, Greece, and Florida, at the southeast, have each a large archipelago southeast of them;

13

of the coast islands of Asia, the Galapagos and Sandwich groups of the Pacific, and Iceland, the Azores, Cape Verde, St. Helena, and Ascension of the Atlantic, are volcanic islands.

Coral islands are those composed of coral, a limy substance formed from sea-water by certain small animals, and are found only in the warmer parts of the ocean. They are usually small and low. The Bahamas and Bermudas in the Atlantic and many oceanic chains in the Pacific are coral islands.

Questions (I.)—1. How are most islands arranged? What are some of them? -2. How many kinds of islands? What are they?-3. What are continental islands? Where are the principal chains of continental islands?-4. What are oceanic islands? Where are the principal chains?

(II.) 4. Name some oceanic islands. What are volcanic islands? What kind of shores and surfaces have they? To which class do they belong? Name some volcanic islands of the Pacific. Of the Atlantic. What are coral islands? Where found? Of what size? Name some coral islands.

the great rivers of the globe; their cold summits temper the fierce heat of the Torrid Zone; in them are found most of the metals and other minerals so important to the well-being of man.

Questions (I.)—1. What is a mountain system ?-2. Where is the longest system? How long is it?-3. Describe the chief system of the Old World. How long is it? Of what is it composed?-4. Where are volcanoes chiefly found? Where are none found?-5. State some of the uses of mountains.

(II.)-2. How many divisions has the great mountain system of America? What chains in each? Where is its highest point? How high is it?-3. Which are the highest mountains in the Old World? How high is their highest peak? What other mountains in the same system? Where are the two great systems? Where is the principal system of Africa? Of Australia? With what are the tops of many of the great mountain chains covered?-4. Where are most of the volcanoes of the Western Hemisphere found? Of the Eastern? What oceanic islands contain volcanoes? Where are most of the volcanoes of the world found?

XVI. MOUNTAINS.

1. A mountain system is a number of nearly parallel ranges covering a wide belt of country.

2. The New World has the longest mountain system; its length is about ten thousand miles.

It has two principal divisions-the Andes chains in South America, and the Rocky Mountains and parallel chains in North America. Its highest point is in South America, and is about 25,000 feet, or 43 miles, above the sea.

3. The chief system of the Old World begins on the Atlantic shores, and extends in an irregular line to the Pacific. It is about eight thousand miles long, and is composed of many smaller systems.

Among them are the Himalaya Mountains, which are the highest in the world, the Caucasus, and the Alps. The highest point of the Himalaya Mountains is about 29,000 feet, or 5 miles, above the sea-level.

These two great systems are not far from the shores of the continents in which they lie. The principal systems of Africa and Australia lie near their eastern coasts.

The tops of many of the great mountain chains are always covered with snow, even in the Torrid Zone.

4. Volcanoes are found chiefly in mountainous islands, or in mountain ranges which are near the sea. The great lowland plains have no volcanoes.

The volcanoes of the Western Hemisphere are mostly found in its great mountain systems; those of the Eastern, in the island chains bordering the coasts of Asia. Many of the oceanic islands

in the Pacific contain volcanoes. Most of the volcanoes of the world are in the Pacific Ocean or near its borders.

5. Mountains are of great importance: they condense a large part of the moisture that falls from the atmosphere as rain or snow; they contain the sources of nearly all

XVII.

PLATEAUS OR TABLE-LANDS.

1. The great plateaus of each continent are in the same regions and lie in the same direction as the chief mountain systems.

These mountains either stand upon the plateaus or form their border walls.

2. The chief plateau belt of North America extends from the isthmus of Tehuantepec to the Arctic Ocean.

Its highest part, the plateau of Mexico, is from 4000 to 8000 feet above the level of the sea. The Rocky Mountains divide these plateaus into two sections: the eastern section is known as the Great Plains; the western section is covered with numerous parallel chains of mountains.

3. The chief plateau belt of South America extends in a band parallel with the western coast.

Its highest and widest part, the plateau of Bolivia, is more than 12,000 feet above the sea. Its edges are formed by two great chains of the Andes. In the eastern part of South America there are low and broad plateaus.

4. The plateaus of Asia are the highest and most extensive in the world.

The plateau of Thibet is the highest; it reaches an elevation of 16,000 feet. It is bordered on the south by the Himalayas.

5. The plateaus of Africa cover nearly the whole of that continent.

The highest is east of the Nile River, and is from 6000 to 7000 feet in elevation. Africa is bordered on nearly every side by mountains. The Atlas, Snowy, and the ranges near the eastern coast are the principal chains.

6. The plateaus of Australia are comparatively low. This continent resembles Africa in its almost unbroken coasts and mountain borders.

14

7. Europe has no large plateaus.

8. Nearly all deserts are plateaus.

Questions (I.)-1. Where are the great plateaus of each continent found? In what direction do they lie?-2. Where is the chief plateau belt of North America ?— 3. Of South America?-4. What is said of the plateaus of Asia?-5. What is said of the plateaus of Africa ?—6. Of the plateaus of Australia?—7. Of Europe?-8. What is said of deserts?

(II.)-1. What relation have the mountains to the plateaus with which they are connected?-2. What name is given to the highest plateau of North America? How high is it? How do the Rocky Mountains divide these plateaus? What name is given to the eastern section? What is the character of the western section ?-3. What name is given to the highest plateau of South America? How high is it? What mountains border the high plateaus of that continent? Where are its low plateaus ?— 4. What name is given to the highest plateau of Asia? How high is it? What mountains border it ?-5. Where is the highest plateau of Africa? How high is it? How is that continent bordered? Name the principal chains.-6. In what respects does Australia resemble Africa?

XVIII.

LOWLAND PLAINS.

1. The great lowland plains of the American continents lie between the high plateaus and the coasts of the Atlantic Ocean, from which they are partly separated by low plateaus and mountains.

The great lowland plains of Europe and Asia lie between the high plateaus and the shores of the Arctic Ocean.

These plains are the most extensive in the world. Their greatest length is in the same direction as the principal mountain systems and the belts of plateaus. Smaller but important plains are found in other parts of these four continents.

2. The lowland plains of Australia lie in the central and southern portions of that continent.

The greater part of these plains is yet unexplored. Africa has no large and important lowland plain. 3. The most fertile soil and the largest navigable rivers are found in the low plains of the Torrid and Temperate Zones.

The greater part of the population of the world, and the chief seats of civilization, are found in these plains. The most densely populated are the plains of China, of the Ganges, and the western part of the great plain of Europe.

More than one third of the population of North America inhabit its central plain.

4. The plains which border the Arctic Ocean are among the coldest regions of the globe.

Questions (I.)-1. Where are the great lowland plains of the American continents? By what are they partly separated from the Atlantic? Where are the great low plains of Europe and Asia?-2. Of Australia? Of Africa?-3. What is said of the plains of the Torrid and Temperate Zones ?-4. Of those bordering the Arctic Ocean?

(II.)-1. Which are the most extensive plains in the world? In what direction is their greatest length? Are there any other important plains in these four continents? -2. What can you say of the lowland plains of Australia?-3. What are found in the plains of the Torrid and Temperate Zones ? Name the most densely populated. How much of the population of North America inhabits its central plain?

XIX.

THE OCEANS.

1. The Pacific Ocean is about as large as all the other oceans taken together.

It is remarkable for the number of its islands and border seas; these seas are enclosed or partly enclosed by curved lines of islands.

2. The Atlantic Ocean is about half as large as the Pacific.

It is remarkable for the many inland seas that branch from it, and for the number of great rivers that flow into it. Its northern half is the chief theatre of the ocean commerce of the world. 3. The Indian Ocean is much smaller than the Atlantic.

It is remarkable for the fewness of its seas and islands, and for the violence and frequency of its hurricanes.

4. The Arctic Ocean is much the smallest of the

oceans.

It is a part of the Atlantic rather than a separate ocean. All the great plains border on the Atlantic and Arctic Oceans. 5. The Antarctic or Southern Ocean is not properly a separate ocean, but a combination of the southern parts of the three great oceans.

It is remarkable for the intensity of its cold, and for the number and size of its icebergs.

The greater part of the polar oceans, and especially the Antarctic, has never been explored.

Questions (I.)—1. What is said of the size of the Pacific Ocean?-2. Of the Atlantic?—3. Of the Indian?-4. Which is the smallest ocean?-5. Is the Antarctic Ocean a separate ocean? What is it?

(II.)—1. For what is the Pacific Ocean remarkable? By what are the border seas enclosed? Name four of the border seas of the Pacific Ocean. (See maps of hemispheres.)-2. For what is the Atlantic Ocean remarkable? What is said of its commercial importance? Name four inland seas of this ocean. Name two great rivers flowing into it from North America. Three from South America. One from Africa. -3. For what is the Indian Ocean remarkable? Name the two great bays of that ocean.-4. Of what ocean is the Arctic a part? Name the three continents surrounding it. What lands border on these two oceans?-5. For what is the Antarctic Ocean remarkable? Have the polar oceans been explored? Why?

XX.

DRAINAGE WATERS.-RIVERS.

1. The ocean is the source of all the waters upon the surface of the land.

The winds and the heat of the sun are constantly carrying away invisible vapor from the surface of the ocean; this forms clouds, and falls upon the land as rain or snow. This water leaves the iand surface in three ways: first, the greater part is evaporated; second, a part flows directly away, forming lakes, rivers, and smaller streams; third, a part sinks into the soil, and issues again at a lower level as springs.

15

2. Many large rivers have their sources in the snowcovered mountains of the table-lands.

Most rivers begin at springs, and are enlarged by rains and melted snows, and by other rivers.

3. A river system is a river with its branches.

A basin or valley is the whole country drained by a

river system.

A water-shed is the line of highest land that divides two basins.

In the United States it is sometimes called a divide.

An estuary is a broad mouth of a river. When a river enters the sea by two or more mouths, the land between the mouths is called a delta.

A cañon is a deep and narrow gorge through which a river runs. Rapids are those parts of a river in which the current is very swift. Falls are those parts of a river in which the water flows over a precipice. Falls of small streams are called cascades; of large rivers, cataracts.

4. The rivers in the low plains are the chief natural channels of commerce, especially since the invention of the steamboat, by means of which their swift currents may be ascended. Commerce is less expensive by water than by land.

In the hill countries, rivers whose falls or rapids interrupt navigation furnish valuable water-power for manufacturing purposes.

Some rivers overflow their banks at certain seasons, and by a rich deposit of mud fertilize the low lands through which they run.

Where rivers run through lands which are very dry during the summer, their water is sometimes used to irrigate the soil.

Questions (I.)-1. What is the source of all the waters which are on the surface of the land?-2. Where do many large rivers have their sources ?-3. What is a river system? What is a basin or valley? What is a water-shed?-4. State some of the uses of rivers.

(II.)-1. How is water constantly taken from the surface of the ocean? In what form does it fall again? In how many and what ways does it leave the land surface again?-2. At what do most rivers begin? How are they enlarged?-3. What is a divide? An estuary? A delta? A cañon? What are rapids? Falls? Cascades? Cataracts?

XXI.

LAKES.-GLACIERS AND ICEBERGS.

1. Lakes are of two kinds-salt and fresh.

2. A salt lake is one that has no outlet.

Small quantities of salt are washed out of the soil by the rains; if carried to a lake having no outlet, the salt is left in the lake by the evaporation of the water.

3. The plains and plateaus of Asia have the largest salt lakes in the world.

The largest of these are the Caspian and Aral seas.

4. The plains of North America and the plateaus of Southern Africa have the largest fresh-water lakes in the world.

Their principal outlets are the St. Lawrence and Nile Rivers. Titicaca, on the plateau of Bolivia in South America, is the most elevated of the large fresh-water lakes: it is 13,000 feet above the ocean-level.

5. Glaciers are vast river-like fields of ice. They are formed from snow, which is solidified by the pressure of its own weight, and by melting and freezing.

They are formed in the high mountain valleys in the regions of perpetual snow. They move very slowly down the valleys-only a few rods in a year. In the Temperate Zones they are found in the highest part of the highest mountains, as in the Alps and the Himalayas. In the Frigid Zones their lower edges project into the sea; the tides and waves here wash away their bases, and the overhanging portions at last break off by their own weight and fall into the sea: they are then called icebergs.

Questions (I.)-1. How many kinds of lakes? What are they?-2. What is a salt lake?-3. Where are the largest salt lakes in the world?-4. Where are the largest fresh-water lakes in the world?-5. What are glaciers? How are they formed?-6. What is an iceberg?

(II.)-2. How is a salt lake formed?-3. Name the two largest salt lakes.-4. What are the outlets of the largest fresh-water lakes? Which is the most elevated of the large fresh-water lakes? Where is it? How high?-5. Where are glaciers formed? Describe the origin of an iceberg.-6. What can you say of the glaciers and icebergs of Greenland? Of the Antarctic Ocean? Where are they formed?

1. An ocean current is a broad stream of water flowing through the ocean.

The great ocean currents are so connected with each other as to form a circulatory system; some of them are of great depth. 2. Constant currents are those that always flow in the same direction.

Some of them have been traced many thousands of miles. All the
rivers in the world are insignificant when compared with some
of these currents. The chief cause of ocean currents is the dif-
ference of temperature of the ocean waters in the Torrid and
Frigid Zones: the warmer and lighter water flows towards the
poles, an equal quantity of the colder and heavier water flowing
at the same time towards the Equator. The ocean currents thus
assist to cool the tropical and to warm the polar regions.
The direction and velocity of currents are modified, first, by the
earth's revolution on its axis; second, by the constant winds of
the Torrid Zone; third, by being turned aside by the shores.

XXIII. WINDS.

1. The atmosphere covers the earth to a height of about fifty miles.

The upper portions of the atmosphere press upon the lower, and
make them denser. Nearly all the moisture and all animal and
vegetable life are found within three and a half miles of the
level of the sea. Above this the thinness and dryness of the
atmosphere, and the intense cold, render plant life, and conse-
quently animal life, impossible.

The mountains of Thibet have been ascended above four miles.
A balloon has reached an elevation of five and three-quarter
miles. These are the greatest heights ever reached by man.
In both cases the suffering was very great.

2. Heat causes air, first, to expand and become lighter; and, second, to absorb and render invisible large quantities of water. Cold produces opposite effects.

3. The heat of the sun produces ascending currents of hot air, particularly in the Torrid Zone; other air flows

est of the constant currents.

They are found in the Atlantic and Pacific oceans, and move from east to west.

4. The most important current is the Gulf Stream. A division of the Equatorial Current passes along the outer or ocean shores of the West Indies. A branch from this enters the Caribbean Sea and again subdivides. One part passes eastward along the shores of Hayti, and rejoins the outer current. The other part passes through Yucatan Channel, and issues from the Strait of Florida as a swift and deep current known as the Gulf Stream. It rejoins the outer current at the Bahamas, and gives its own name to the entire current, which then crosses the Atlantic in a northeasterly course, and, with the winds which sweep over its warm waters, gives a mild climate to Western Europe. 5. The Japan Stream, a current similar to the Gulf Stream, passes from Japan towards North America.

6. The Polar Currents are the cold currents passing from the polar regions towards the Equator.

4. Winds are currents of air.

"The currents from the polar regions tend at first directly towards the Equator; as they pass towards and into the Torrid Zone, the revolution of the earth on its axis causes them to turn more and more towards the west these currents are then called the Trade Winds.

5. The Trade Winds are constant winds between the parallels of 30° north and south latitude, and always blow from an easterly direction. They carry immense quantities of vapor from the Atlantic, Pacific, and Indian oceans.

The masses of heated air rise some miles from the surface of the earth, and flow over in two sets of currents, one towards each pole, to fill the places left vacant by the Polar Currents; they gradually cool and settle towards the surface, striking it beyond the parallels of 30°: they are then known as the Return Trade Winds, or Counter Trade Winds.

is known of the cold currents which flow at the bottom of the ocean. The ocean water at great depths in the Torrid Zone is nearly as cold as that in the Arctic Ocean. The two broad oval spaces between the Equatorial Currents on the south and the Gulf Stream and the Japan Stream on the north are called Sargasso or Grassy seas, because covered with floating sea-weeds.

Questions (I.)-1. What is an ocean current ?-2. What are constant currents?— 3. Which are the greatest of the constant currents?-4. Which is the best known current?-5. Describe the Japan Stream.-6. Describe the Polar Currents.

(II.)—1. How are the ocean currents connected? What is said of their depth ?— 2. How far have some been traced? How do they compare with rivers? What is their chief cause? Of what use are they? How are their direction and velocity modified?—3. Where are the Equatorial Currents found? What is their general direction?-4. Describe the origin and course of the Gulf Stream. How does it affect the climate of Western Europe?-6. What do the Polar Currents bring from the polar regions? What is said of the deep cold currents? Of the deep water in the Torrid Zone? Where are the Sargasso or Grassy seas? Why so called?

Southern from the northwest.

The Trade Winds and Counter Trade Winds are similar to the ocean currents both in cause and general direction.

Questions (I.)—1. To what height does the atmosphere extend?—2. What are the effects of heat upon air? Of cold?-3. What are the effects of the sun's heat? In what zone is this effect most marked? What other effect follows?-4. What are winds?-5. What and where are the Trade Winds? What is their direction? What do they carry?—6. What and where are the Counter Trade Winds? In what direction do they blow?

(II.)-1. How do the upper portions of the atmosphere affect the lower? What are found only within three and a half miles of the level of the sea? Why is there no life above this height? What are the greatest heights ever reached by man? What was the effect?-4. In what direction do the Polar Currents at first flow? In what direction afterwards? What causes this change? What are they then called?-5. Describe the course of the ascending currents of the Trade Winds. Where do they again strike the surface of the earth? What are they then called?-6. In what respects are the Trade Winds similar to the ocean currents?