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Geography - More Suggestions On Lessons

( Originally Published 1915 )



WINDS

THERE are great rivers of water in the ocean called ocean currents, such as the Equatorial Current, Gulf Stream, and Japan Current, that are continuously moving in fairly definite courses. So, too, in the atmosphere, there are great rivers of air called wind currents or winds that also move in more or less definite courses.

The air is very unstable and is therefore easily moved by outside forces. The principal forces that influence its movements are heat, moisture, and the rotation of the earth. Heat, as was pointed out in Form II, causes air to expand and thus makes it lighter in 'weight ; moisture also makes it lighter; the rotation of the earth influences its direction.

The lighter air rises as the cooler and heavier air at the sides flows under it and lifts it up. When the air becomes lighter than usual, its pressure is said to be "low". Hence high pressure means a heavy atmosphere ; and low pressure, a light atmosphere. These conditions are indicated and measured by the barometer. A fall in the barometer usually precedes a rainstorm. Why? Heated regions are always areas of low pressure; and cold regions, unless counteracting agencies are at work, are areas of high pressure. Winds always blow from areas of high pressure to areas of low pressure.

In areas of low pressure, where warm air is rising to form upper currents, or in areas of high pressure, where cool air is falling to form surface currents, areas of calms are formed: Hence, air currents moving along the surface of the earth produce winds, while those moving either upward or downward produce calms.

What is the greatest area of low pressure in the world? Why is it situated in the equatorial region? What name is given to it? This Doldrum region is one of great calms. Why? (See Text-book, page 38.) Where does this region get its supply of air ? It is continuously rushing in as great surface currents from the north and from the south. What name is given to these winds? These trade-winds, as they are called, begin to blow at about the 30th parallel of latitude. In the northern hemisphere they blow from the north-east, and in the southern hemisphere from the south-east. Why?

The trade-winds are usually fresh and strong, and sailing vessels may go on for days without changing sail. These are the winds that carried Columbus with his three small ships across the Atlantic Ocean on his voyage to America in 1492. They are dry winds when they begin to blow, but when they reach the doldrum region they are almost saturated with moisture. How would you explain this? (See Text-book, page 37.) As the trade-winds travel toward the doldrums, they are gradually becoming warmer and warmer, and will therefore absorb more and more moisture. This makes them drying winds. What is the effect of these winds upon the lands over which they blow? What causes the Desert of Sahara?

What becomes of this flow of warm, moist air when it reaches the doldrums? Describe the climate of the doldrums. (See Text-book, page 38.) What becomes of the air that rises in the doldrums? Have we any evidence that, after it rises to a great height, it flows off toward the poles? From observations made in the region of the West Indies and in the Caribbean Sea, as well as elsewhere where the trade-winds are blowing toward thé south-west, one may see clouds at a great altitude being carried in the opposite direction. Locate on a globe or map the trade-wind regions with the doldrum region lying between. (See Ontario High School Physical Geography, page 201.)

What becomes of the upper air currents that flow from the doldrums off toward the poles? A large portion falls to the surface at about the 30th parallel of latitude. Here we find in both the northern and southern hemispheres, a region of calms and light winds. This is the area of highest pressure in the world. Why are calms 8e prevalent here? By what name is this region known? What becomes of the air that is falling in these *Horse Latitudes? It is the source of supply for the trade-wind systems as well as for two other great wind systems known as the Prevailing Westerlies.

Why are the Prevailing Westerlies so called? When they leave the horse latitudes, they take a long sweep toward the east-northeast in the northern hemisphere, and toward the east-southeast in the southern hemisphere; in both cases they finally reach the polar regions. Why are these winds more uniform in the southern hemisphere than in the northern? Explain why it is easier for ships sailing from England to Australia to go by way of the Cape of

*It is said that the Horse Latitudes were so named be-cause sailing vessels, carrying horses from New England to the West Indies in the early days, were so delayed by the calms that at times the horses had to be thrown overboard when the drinking water gave out.

Good Hope than by way of Cape Horn. Which is the better route for the return voyage? Why?

The prevailing westerlies that blow over Canada and the Atlantic Ocean are somewhat variable; they blow on an average about two days out of every three throughout the year. For example, the average time of a sailing voyage from Liverpool to New York is thirty-three days; and from New York to Liverpool, twenty-two days. How do these prevailing westerly winds greatly affect the climate of British Columbia? Of the British Isles? Locate, on a globe or a map of the world, the regions over which these winds blow.

The Monsoon Winds of Southern Asia and the Indian Ocean are modified trade-winds—trade-winds that change with the season. From October to April they resemble the ordinary north-east trades, blowing from Asia over the Indian Ocean. Europeans in India find these months the pleasantest and most healthful part of the year. From April to October, however, the plateaus of Southern and Central Asia become so greatly heated that they become areas of low pressure—lower pressure than that over the Indian Ocean. The result is that the winds, instead of blowing from the north-east, turn completely around and blow strongly and steadily from the south-west. They bring excessive rains, and the weather becomes so hot and the humidity so great that many Europeans in India are forced to go to the foot-hills of the Himalayas for comfort and health.

The above is a general description only of the more constant winds. Owing, however, to the instability of the atmosphere, to frequent changes in heat conditions, as well as to various other causes, there are endless modifications in the character of winds. Some of the more important of the variable winds are the polar winds, land and sea breezes, day breezes and night calms, thunder-storms, the common cyclonic or cycle storms of the Eastern United States and Eastern Canada, and the destructive tornadoes. Excellent supplementary material may be found in Chapter XI of the Ontario High School Physical Geography. Study the diagrams on page 38 of the Text-book until the location and direction of the principal winds are under-stood.

ZONES OF SUNLIGHT

What parts of the earth's surface receive most heat from the sun? Those parts upon which the sun's rays fall vertically. 'Where is the location of the farthest north point upon which the sun's rays are vertical? It is on the Tropic of Cancer. What is the latitude of the Tropic of Cancer? 23 1/2° north. Similarly show that the farthest south point upon which the sun's rays are vertical is . the Tropic of Capricorn, 23 1/2° south. Hence, the only portion of the earth's surface that receives the direct or vertical rays of the sun some time during the year is located between the two tropics. This region extends like a belt around the earth and is called the Torrid Zone. It receives more light and heat than any other region on the earth. How many degrees in width is this zone ?

How much of the earth's surface will receive rays of sunlight at any one moment? One half of its surface. Hence, when the sun is shining vertically down upon any one point, how far on all sides of this point will the earth receive rays of sunlight? Ninety degrees. Illustrate this by means of a candle and globe.

Hence, when the sun is shining vertically down upon the Tropic of Cancer, note that its rays will fall 23 1/2 degrees beyond the North Pole, that this determines the latitude of the Arctic Circle, that the whole region within the Arctic Circle is in sunlight, and that the rays of the sun are very slanting since the sun is so near the horizon. Note, also, that at the same time the rays of the sun fall short of the South Pole 23i degrees, that this deter-mines the latitude of the Antarctic Circle and that the whole region within the Antarctic Circle is without any sunlight whatever. Six months later these conditions are reversed. It is because these polar regions receive so little light and heat from the slanting sun's rays that they are called respectively, the North Frigid Zone and the South Frigid Zone. (See diagrams, page 15, Text-book.)

Between the Tropic of Cancer and the Arctic Circle in the northern hemisphere, and between the Tropic of Capricorn and the Antarctic Circle in the southern hemisphere are regions that are not so extremely hot as the Torrid Zone and not so extremely cold as the Frigid Zones. They are regions of moderate temperatures, and hence are known, respectively, as the North Temperate Zone and the South Temperate Zone. Unlike the Frigid Zones, the sun shines upon them every day of the year; its rays do not fall so slantingly upon them and hence are warmer. Unlike the Torrid Zone, no vertical rays of the sun ever fall upon them and therefore they are not so hot. How wide are the Temperate Zones? Each is 90—(23 12/+23 1/2) or 43 degrees wide.

In which Zone is Canada? What other countries are in the North Temperate Zone? What countries are in the South Temperate Zone? In the Torrid Zone? Draw a circle; indicate the two polar circles and the two tropics; write in the names of the five zones of sunlight.

What instrument is used to measure the temperature of the air? How does the temperature vary during the day? It is usually warmer in the daytime than it is at night. What is the reason of this? By using special kinds of thermometers we are able to learn the highest and lowest temperatures for each day. If the highest temperature recorded on a certain day is 86 degrees and the lowest 52 degrees, what was the average temperature for that day? It was 69 degrees. How is the average yearly temperature of any place calculated?

What name is given to an imaginary line drawn around the earth connecting the places that have the same average yearly temperature? It is called an isothermal line, or isotherm. Do these isotherms form circles around the earth like the parallels of latitude? Why not? It is because the earth is not evenly heated.

Which warms faster, the land or the ocean? Why does the ocean not become as warm as the land under equal heat conditions? It is because the ocean has currents to carry the warmer water away to cooler places. It is because of this that the ocean has a more equable climate than the land. Why does an isotherm reach a higher latitude when it is crossing a continent than when it is crossing an ocean? (See Ontario High School Physical Geography, pages 184-187.)

What name is given to the isotherm passing through those places that have the greatest average temperature in the world? It is called the Heat Equator. Why is this heat equator not a circle like the geographical equator? Why does the heat equator change its position during the year? Why is its average position during the year always north of the geographical equator? It is because the northern hemisphere has more land than the southern hemisphere that it is warmer than the latter.

Extending around the earth on both sides of the heat equator is a broad region known as the Hot Belt. Its northern boundary is the northern isotherm that has an average yearly temperature of 68 degrees. Its southern boundary is the southern isotherm of 68 degrees.

Around the north pole is an extremely cold area called the North Cold Cap in which the average temperature is never above 50 degrees. It takes at least 50 degrees to ripen the hardiest grains. What isotherm will therefore form the southern boundary of the north cold cap? Deal similarly with the South Cold Cap.

Between the hot belt on the south and the north cold cap is a region known as the North Temperate Belt. What is its northern boundary? Its southern boundary? What range of temperature has this belt? Its average temperatures range between 50 degrees and 68 degrees. Deal similarly with the South Temperate Belt. Why is the north temperate belt much wider than the south temperate belt? It is because the former has a greater land area than the latter. Explain.

Consult the map and note that the north temperate belt embraces the most progressive countries in the world, including Canada, the United States, all the countries of Europe, and China and Japan.

Draw a map of the world on Mercator's projection and show the general location of these heat belts, distinguishing them by different colour shadings.

SUGGESTIONS FOR A SERIES OF "TALKS" ON THE EVOLUTION OF THE BRITISH EMPIRE

To obtain a proper perspective of the British Empire as at present constituted, some of the geographical and historical factors that have been co-operating in its development should be considered.

1. In all ages and among all changes of inhabitants the insular character of Britain has been one of the ruling factors of its history. Its people, of whatever race or speech, whatever their political condition at home or their political relation to other countries, have been above all things pre-eminently islanders—cut off in many ways from the rest of the. world, acting in many things as a separate world.

2. There settled early in England roving, adventurous, liberty-loving Anglo-Saxons, and their roving, adventurous spirit has been transmitted to the succeeding generations of the British people. These were not content to stay within the limits of their little home islands, and many went forth, especially during the sixteenth, seventeenth, and eighteenth centuries, as sailors, explorers, and colonizers. As they discovered new regions, they took formal possession of them in the name of their Mother-country. In this way, and by war, Britain came into possession of Canada, India, Australia, New Zealand, and South Africa, as well as the smaller colonies scattered over the world.

3. Thus, from small beginnings the British Empire has grown until to-day it stands first among the nations in wealth, power, area, and population. It occupies over one fifth of the land surface and includes more than a quarter of the total population of the world. In this population are represented practically all the races and gradations of human society correlated within the jurisdiction of one paramount state. The position of the British Islands at the centre of the land hemisphere helps greatly to explain the enormous extent of British commerce.

4. The Saxon brought with him to Britain the democratic spirit in government and democratic form of government—popular representation of the governed. "A germ of political and social life was brought into Britain which, changing from generation to generation but never itself exchanged for any other system, borrowing from foreign sources but assimilating what it borrowed with its own essence, changing its outward shape but abiding untouched in its true substance, has lived and grown through fourteen hundred years into the law, the constitution, the social being of England."—FREEMAN. Since the war of American Independence, Great Britain has governed her colonies in such a way as to advance their interests, and not merely for her own advantage., Autonomy has been granted as soon as they have been able to assume responsibility. A spirit of toleration for language ana religion, a belief in the supremacy of law and in personal and political freedom, a recognition of mutual rights and privileges have marked the administration of Great Britain in every quarter of the globe.

The sea which sheltered England from the armies which devastated much of Europe had accustomed the' Britons to the handling of ships. Henry VIII created the English navy and improved it year by year. Elizabeth claimed the freedom of the seas in 1580; and in 1588, by the destruction of the Armada she broke the monopoly of the seas then claimed by Spain. The struggle later for the empire of the sea lay between France and England and ended at Trafalgar. Since then Britain has maintained that supremacy at sea which is the condition of her existence.

The unity of the Empire depends for its strength upon a common ancestry, common ideals, a community of interests, and a loyalty bred from the traditions and history of a glorious past. The supremacy of the Empire is a guarantee of peace and justice throughout the world. Our task and aim should be to fit ourselves, by closer union, to maintain its limits and extend its influence.

CANADA'S RELATIONSHIP TO THE EMPIRE

In considering Canada's relation to Britain and the rest of the Empire, the following points, among others, should receive attention:

1. How Canada became a part of the British Empire.

2. How the favourable terms granted to the French-Canadians by the Treaty of Paris (1763), and their contentment under British rule, have made them loyal to Britain and to British institutions.

3. How a strong stimulus was given to loyalty to British connection by the settlement in Canada of thou-sands of United Empire Loyalists at the close of the American War of Independence.

4. How this loyalty was greatly intensified by the War of 1812-15.

5. How the principle of self-government, gradually conceded by Great Britain, tended to make Canadians contented with British connection.

6. How the Boer and the German Wars tended to strengthen- Imperial patriotism and -Canadian national self-respect.

7. Canada's present status may be summed up as follows :

(1) The British Government appoints the Governor-general; and may veto, within two years after passing, any Act of the Cana-

dian Parliament which it may regard as detrimental to the interests of the Empire. It would be only under the most grave circumstances that we can conceive of this power being exercised.

(2) Canada has fiscal independence, but gives a "preferential tariff " to the Mother-country and to most of the other parts of the Empire, except Australia.

(3) Canada has assumed, with the concurrence of the British Government, the full responsibility of maintaining a permanent military force, militia, and navy for her own defence, and in so doing is relieving the Mother-country of a part of her heavy Imperial responsibilities.

(4) Canada has not yet any voice in the declaration of war or peace; the Imperial Government alone has this power.

(5) The highest court of appeal is the Judicial Committee of the Imperial Privy Council.

(6) The strongest tie binding Canada to the rest of the Empire is the one of sentiment, based chiefly upon community of interest and of blood relationship.

(7) In other respects Canada is virtually an independent country with full control of her affairs.



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