they frequently accompany. Thus the climate of the western coasts both of Europe and of North America is rendered milder and moister by the prevailing south-westerly winds and the Equatorial currents; while, as already explained, the east coast of North America has its temperature lowered by the Arctic current which sweeps round its coasts, and the cold north-east winds which accompany it.

QUESTIONS.-What is meant by the climate of a place? By what is it chiefly determined? Mention instances of places in the same latitude having very different climates. What are the chief secondary causes to which these differences are due? Why does temperature diminish with elevation? What aspect produces the mildest climate? Mention a striking case of difference of climate depending on aspect. What is the difference between an insular

and a continental climate? Why is the former the more temperate ? Contrast Moscow and Edinburgh in respect of climate. Give an instance of mountain ranges making a climate milder. What is the effect on climate of clearing forests and improving drainage? What is the difference between winds that originate on continents and those that rise on the ocean? Give examples of climate ameliorated by winds and currents.

IV.-PLANT LIFE.

Different plants are characteristic of different latitudes and different elevations above the sea-level. Humboldt has divided the Earth, from the Equator to the Pole, into eight vegetable zones, as follows:

As in the case of climate, the zones of vegetation vary in the same latitude with the elevation above the sea-level. For example, on the sides of the Mexican mountains there are representatives of the plants that grow in every part of the world, from the Equator to the Polar regions.

Plant life depends, for its forms and abundance, upon climate and the character of the soil. Plants grow best where they have both heat and moisture; and, accordingly, vegetation is most luxuriant in regions between the Tropics. But plants of some kind grow on every part of the globe, and have been wonderfully adapted by the Creator to the conditions in which they may best fulfil the end of their being.

QUESTIONS.-Into how many vegetable ample. Upon what does plant life depend zones has Humboldt divided the Earth? Name them. Name plants characteristic of each. How do these zones exist together in the same latitude? Give an ex

for its form and abundance? What is the cause of the luxuriance of tropical vegetation? To what are different classes of plants wonderfully adapted?

V.-ANIMAL LIFE.

The distribution of animals is chiefly determined by climate and ply of food. For food, they depend on the vegetable kingdom; those which do not live on vegetables feed on those that do. Within a the Tropics the supplies of food are most plentiful; and there, th animals are most abundant and varied, attain the greatest size, and the brightest colours. Nothing can exceed the richness of colouri variety of the birds and insects in these regions; while there, also, th mammalia,- -as the elephant and the rhinoceros, the lion and the reach their highest development.

From the Tropics to the Poles animal life gradually dwindles, both number of its types and in the appearance of them, as well as in th over which they range. The range of animals is limited by the n barriers which prevent their passage from place to place; but still more cially in the case of birds) by the conditions to which their life is ad Man, also, has come to exercise great influence over the inferior an by rooting out those that are destructive or hostile to him, and prom the increase of those that are useful.

Certain animals are characteristic of certain countries;-the elepha India and Africa; the lion, of Asia and Africa; the kangaroo, of Austr the reindeer and the bear, of the Polar regions; the bison, of North Ame and the jaguar, of South America.

The animals most useful to man are the ruminants,-ox, sheep, ca goat, llama, deer,-and the horse tribe; and these are more widely diff over the world than any others.

QUESTIONS.-What chiefly determines the distribution of animal life? On what do all animals ultimately depend for food? Where is that food most plentiful? What therefore is the character of animal life in the Tropics? By what is the range of animals limited? By what also, especially in the case of birds? How has man influenced

the animal kingdom? Mention ani characteristic of India and Africa; of and Africa; and of Australia. Of v regions are the reindeer and the bear c acteristic? What is characteristic of No America? and of South America? W animals are most widely diffused? W is this a beneficent arrangement?

VI.-MAN.

There are no organic differences among men, as there are among an mals. The different races of men are only varieties of a single stock. The differ from one another in colour, in features, in habit, and in character but in their organic structure, and in the union of the physical and mora elements of life, they are essentially one.

The peculiarities of the different races are probably due to climate, food mode of living, and mental culture. But intercourse among nations of which civilization is both a cause and an effect, tends to break down peculiarities; and along the boundary lines the several races shade off into one another, and thus new varieties are produced.

There are two kinds of evidence according to which mankind may be classified; the evidence of language, or philology; and the evidence of form

and feature, or physiology. The study of languages has established the common origin of tribes far removed geographically from one another, and formerly believed to be quite distinct. But neither philology nor physiology has yet supplied sufficient information to make a final classification possible. According to the results which have already been reached, the human species is distributed into five principal varieties :

1. The Caucasian, or White Race, characterized by an oval head, regular features, and abundant hair. It occupies all Europe (except Lapland, Finland, and part of Hungary); Western Asia; Northern Africa; and the countries in America colonized by Europeans. Philologically it is divided into the Aryan family (Europeans, Persians, Indians) and the Semitic family (Arabs, Jews, Berbers, Moors).

2. The Mongolian, or Yellow Race, with broad skull, oblique eyes, and scanty hair. It includes Chinese, Siberians, Lapps, Finns, Magyars (Hungary), Turks, and Esquimaux. Philologically this and the following races are grouped together as the Turanian family.

3. The Ethiopian, or Black Race, with thick lips, flat nose, and woolly hair. It includes the Negroes of Africa, Australia, Madagascar, and some of the Polynesian islands.

4. The Malayan, or Brown Race, with narrow head, and black stiff hair. It includes the natives of Malacca, and the islands of Malaysia, Polynesia, and New Zealand.

5. The American, or Red Race, consisting of the aborigines of America, with the exception of the Esquimaux.

QUESTIONS.-Wherein do the races of men differ from the species of lower animals? In what do the former differ from one another? In what are they essentially one? To what are peculiarities of race probably due? What tends to break down these peculiarities? In what two ways may mankind be classified? What has been established by philology? What are the five principal varieties of the human

species? By what is the Caucasian race characterized? Whom does it include? Who belong to the Aryan and Semitic families respectively? Who are included in the Mongolian race? By what are its members characterized? Whom does the Ethiopian race include? What are its characteristic features? Where is the Malayan race found? Of whom does the Red race consist?

VII.-THE EARTH AS A PLANET.

The Earth is a planet-one of a number of stars that revolve round the Sun at different distances from that centre.

FORM OF THE EARTH.-The form of the Earth, as of the other planets, is spherical. It is not an exact sphere, however. It is slightly flattened at two opposite points, called the Poles; and it bulges out at the middle, or Equator. The shape somewhat resembles that of an orange. But the flattening or compression is comparatively slight. The Earth's diameter at the Poles is only 26 miles less than its diameter at the Equator. The compression, therefore, is only 13 miles at each Pole. To represent it, a globe 6 feet in diameter would need to be flattened less than a quarter of an inch on each side. A flattened globe of this description is called an oblate spheroid.

The following proofs of the spherical form of the Earth may be mentioned:

1. When a ship comes in sight, first the topmasts and the rigging are seen, lastly the hull. If the surface of the sea were not curved, but a watery plane, we should see the whole ship at once.

FIG. 1.

2. As a ship approaches land, the sailors see the tops of the mountains long before they see objects on the shore.

3. Ships have sailed round the Earth, and have reached the port from which they started without changing their course. In like manner, we can

go round the globe, partly by land and partly by sea.

4. As we travel eastward the sun rises earlier; as we go westward it rises later. When it is twelve o'clock at Greenwich, it is little more than half-past eleven at Dublin. A cable message sent from Ireland at two o'clock on Friday afternoon reaches New York at half-past nine o'clock the same morning! This shows the Earth to be spherical from east to west.

5. As we travel north or south new stars come into view, while those behind us disappear below the horizon. This shows the Earth to be spherical from north to south.

6. In eclipses of the moon, the shadow of the Earth is always circular, which is the invariable form of the shadows of spherical bodies only.

The circumference of the Earth is nearly 25,000 miles (exactly, 24,860 miles). The diameter of the Earth is nearly 8000 miles (exactly, at the Poles, 7898; at the Equator, 7924).

The distance of the Earth from the Sun is 91,725,000 miles.

A railway train, going at the rate of 40 miles an hour, would take 25 or 26 days to go round the Earth; it would take 8 days to go through it; and if it could travel from the Earth to the Sun, the journey, without a single stoppage, would occupy 261 years.

MOTIONS OF THE EARTH.-The Earth has two motions-a daily rotation round itself, or on its axis, and an annual revolution round the Sun. On these two motions depend those changes of climate and season which form the conditions of life on the globe, both animal and vegetable. The effects of both these motions, however, are modified by the important circumstance that the Earth's axis is not perpendicular to the Sun's rays.

DAY AND NIGHT.-The Earth rotates, or turns itself round, in the same way as a top spins, once in 23 hours, 56 minutes, 4 seconds; but as the Earth is at the same time moving on its course round the Sun, it is 3 minutes 56 seconds later each day before the same part again comes opposite to the Sun. This makes in all 24 hours, and is called a Solar Day. The imaginary line on which the Earth rotates is called its Axis. The two ends of the axis are called the Poles,-North and South respectively. It is this daily rotation of the Earth that causes Day and Night; but it is the slope of the Earth's axis that causes the variety in the length of the day on different parts of the Earth at the same time, and on the same part of the Earth at different seasons.

FIG. 2.-NORTHERN WINTER AND SOUTHERN SUMMER.

During one part of the Earth's course, the North Pole leans away from the Sun. Then the days are short and the nights are long in the Northern Hemisphere. The region around the North Pole is for a time thrown out of the range of the Sun's rays entirely, and during that time it is night there.

FIG. 3.-NORTHERN SUMMER AND SOUTHERN WINTER.

In the opposite part of the Earth's course, the North Pole leans towards the Sun. Then the days are long and the nights short in the Northern Hemisphere; and the region which formerly went without day now goes without night.

N

Twice only in the year-namely, at the points midway between those two -is the Sun vertical at the Equator. Then day and night are equal all over the world.