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another. Each was created with properties exactly adapted for the circumstances in which they were designed to live.
These varieties of plants and animals correspond to the varieties of climate upon the earth. The climate of a place depends upon the quantity of heat and of moisture which is found there.
The causes of the varieties of climate are the following :1. The heat of the sun.
This is the chief cause. The sun's rays have most power where they are vertical. Tropical countries are therefore very hot. The further we go from the equator the less vertical are the sun's rays, and so we pass gradually from countries where snow is unknown, to the polar regions where there is ice all the year round.
But so long as the sun is above the horizon of any place, that place is receiving heat; when the sun is below the horizon, it is losing heat. Therefore, since in countries distant from the equator the days are longer in summer, the heat in summer is much greater than in winter; and there is more difference the nearer we are to the poles. This accounts for the short but hot summers of northern countries.
If the earth were a uniform surface, this would be the whole account of the matter, and every place on the same parallel of latitude would have exactly the same climate.
Geographers have divided the surface of the globe into zones or belts, separated by imaginary circles parallel to the equator. The middle is called the tropical zone, on each side of which are two temperate zones, and outside these again two frigid zones.
According to this division our own country is in a temperate zone.
But though this is one cause of the difference of climate, there are others also.
Petropaulovski in Kamtchatka, whose harbour is blocked up with ice from November to May, has nearly the same latitude as Wicklow in Ireland.
Other causes are-.
2. The relative position of land and water. The waters of the ocean are of very equal temperature, and have therefore a tendency to preserve equal temperature where their influence extends. A hot wind is cooled, and a cold wind warmed as it passes over the sea. Hence the climate of islands is in general more equable than that of inland countries of the same latitude. The winters are more mild and the summers more temperate.
There is much more water in the southern than in the northern hemisphere, and the result is that the temperature is more equable. 3. The elevation of the ground above the level of the
As we ascend mountains it always becomes colder; and so even in tropical countries, the highest mountains are covered with perpetual snow; and by descending such a mountain we should pass through all the varieties of temperature, from a polar to a tropical climate.
The great plain of Quito, lying under the equator, enjoys a temperate climate, because it is 9000 feet above the sea.
4. The position of mountain ranges, and the direction in which a country slopes, affect the climate. . The southern ride of the Alps is cultivated 1000 feet
higher up than the northern, because it receives the rays of the sun more directly. The Alps contribute to the warm climate of Italy by sheltering it from the cold northern winds. On the contrary, Erzeroum in Armenia, which is more south than Naples, has almost a polar climate, because it is situated amidst the snowcapped ridges of Mount Ararat.
5. The prevailing winds. The west and south winds, which are most prevalent in the west of Europe, sweep over the Atlantic Ocean, and are therefore mild in their character, and tend to moderate the cold of these countries. The hot southerly wind, called the sirocco, so common in countries round the Mediterranean, owes its character to the great Sahara, over which it passes ; and as the Mediterranean is not extensive enough to cool it, this wind contributes much to makes these countries warm.
In the eastern counties of England, the east winds come from the vast plains of Germany, and have only the waters of our narrow Channel to temper them. Consequently in winter and spring, when these plains are damp and chilly, the east winds are cold and bleak. But in the autumnal months the plains of Germany are dry and sandy, and therefore at this time our east winds are hot and parching.
6. Ocean currents. As the earth moves round from west to east, and the ocean can move freely in its bed, there would from this cause be an ocean current apparently flowing from east to west. But this rotation of the earth produces also another effect. It causes the water to flow from the poles towards the equator. Thus we should have two great movements in the ocean : the one from pole to equator, the other
from east to west. Besides, water has less density when heated than cold. So water being warmed at the equator is made lighter, and flows away towards the poles. Thus there is a continual interchange of hot and cold water over the earth. These currents are variously affected by other currents, by the shores against which they strike, and by other causes.
The most powerful of all currents is that known by the name of the Gulf Stream. This issues from the Gulf of Mexico, where the water becomes heated as in other inland seas of warm latitudes, and so a continual current of warm water flows through the Straits of Bahama, in a north-easterly direction, at the rate of three or four miles. Its speed diminishes as it proceeds farther north, and it is finally lost near the shores of Newfoundland, where it meets the great polar current. The Gulf Stream retains considerable warmth for a great part of its course, and is thought to be one of the causes which renders the climate of our western shores more mild than that of the eastern.
There are, besides, other causes which affect the climate of a particular place,-among which are the nature of the soil and the neighbourhood of forests.
The varieties of climate furnish fresh proof of the wisdom and goodness of the Almighty. This variety is, as has been before said, connected with the delightful variety of the earth's production, and supplies man continually with fresh means of support and fresh sources of enjoyment.
The more we study God's works, the more are we struck by the wonderful contrivances with which they abound. Simple in their operation, they give the most complicated results ; but throughout all the whole shines the Dirine Benevolence, providing by infinite forethought and wisdom for the support and happiness of the various tribes with which He has peopled the earth.
He clothes the lilies of the field, He takes thought for the fowls of the air, the fishes of the sea, and the beasts of the field.
O Lord, our Governor, how excellent is Thy name in all the world !
MILTON ON HIS BLINDNESS. WHEN I consider how my light is spent
Ere half my days,* in this dark world and wide,
And that one talentt which is death to hide, Lodged with me useless, though my soul more bent To serve therewith my Maker, and present
My true account, lest he, returning, chide; “ Doth God exact day-labour, light deny'd ?" I fondly ask: But Patience, to prevent
That murmur, soon replies, “ God doth not need
Bear his mild yoke, they serve him best; his state
MILTON. * The light of mine eyes is, as it were, expended before half my
life is over. + Milton calls sight his one talent, because, being an author, it seems as if the particular way in which he was called to serve God, was by studying and writing books. Being prevented by blindness from doing this, he felt his mind more bent than ever to employ it to God's service. The "day-labour,” which God seemed to ask of him, was to read and write what might be to His glory.