To-day that startling invention of the year 1735 has lost a great deal of its importance. Every day at noon the Greenwich Observatory broadcasts the correct time all over the world. Chronometers are rapidly becoming superfluous luxuries. Indeed, if we are to believe our navigators, wireless telegraphy will eventually do away with all our complicated tables and our diligent calculations and computations. Then that lengthy chapter of finding one’s way across those uncharted seas, where one wave looked so hopelessly much like the next that even the best of sailors could lose himself in less time than it takes to write down this sentence—then that marvellous chapter of courage and endurance and high intelligence will also have come to an end. The imposing man with the sextant will disappear from the bridge. He will sit in his cabin with a telephone clasped to his ear and he will ask: “Hallo, Plymouth! or Hallo, Nantucket! or Hallo, Cherbourg! Where am I?” And Plymouth, or Nantucket, or Cherbourg will tell him. And that will be that.
But these twenty centuries of effort to make man’s progress across the face of the earth safe and pleasant and profitable will not have been in vain. For they represented one of the first successful experiments in international co-operation. Chinese, Arabs, Indians, Phoenicians, Greeks, Englishmen, Frenchmen, Dutchmen, Spaniards, Portuguese, Italians, Norwegians, Swedes, Danes, Germans, one and all did their share to help the good work along (whether unconsciously or intentionally does not matter).
That particular chapter in the history of co-operation has now been dosed. But there remain enough others to keep us busy for quite a long time.
Chapter V
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THE SEASONS, AND HOW THEY HAPPEN
Our word ‘season’ is of Latin origin, and it comes from the verb serere, which means ‘to sow.’ ‘Season’ should therefore be used only to indicate the spring—the ‘sowing time.’ But very early in the Middle Ages ‘season’ lost that exclusive connotation. Three other seasons were added to divide the year into four equal parts: The winter, or wet season; the autumn, the period of increase, and the summer, which was the old Sanskrit name for the entire year.
Aside from their practical and their romantic interest to the human race, the four seasons have a most prosaic astronomical background, for they are the direct result of the earth’s behaviour on its yearly peregrination around the sun, as I shall tell you as briefly and as dully as the subject allows.
The earth turns upon its own axis in twenty-four hours. The earth revolves round the sun in about 365¼ days. To get rid of that ¼ day and keep the calendar more or less pure (no, it is not correct, but it is extremely doubtful whether the nations just now would find time in which to agree upon a decent revision) we have a year of 366 days, or leap-year, every four years except in the years which end with two zeros, such as 900, 1100, 1300, or 1900. But the years which can be divided by 400 are an exception to this exception. The last exception was Anno Domini 1600. The next one will be the year of grace 2000.
The earth does not describe a perfect circle on its way round the sun, but an ellipse. It is not much of an ellipse, but enough to make the study of the earth on its course through space a great deal more complicated than if we had to deal with a perfect circle.
The axis of the earth does not stand at right angles to the plane which we could draw through the sun and our own planet, but at an angle of 66½°.
But on its course round the sun the axis of the earth always remains at the same angle, which is directly responsible for the deviations and the intensity of the different seasons in different parts of the world.
THE ZONES
On March 21 the position of the earth in relation to the sun is such that the light of the sun illuminates exactly one-half of the surface of our planet. As a result, on that particular day, day and night are of equal length in every part of the world. Three months later, when the earth has finished one-fourth of her voyage round the sun, the North Pole is turned towards the sun and the South Pole is turned away from the sun. As a result, the North Pole is celebrating its yearly day of six months while the South Pole is enjoying its yearly night of six months; and the northern hemisphere is partaking of the long, shining days of the summer while the southern hemisphere is spending the long winter evenings reading a good book by the fireside. Remember that when we go skating at Christmas the people in Australia and the Argentine are dying of sun-stroke, and while we suffer from our annual heat-wave it is time for them to light their furnace fires.
The next day of seasonal importance is September 23, because then once more the days and nights are of equal length all over the world. Then we reach December 21, when the South Pole has turned its face towards the sun and the North Pole has turned its back upon our source of heat. Then the northern hemisphere is cold and the southern hemisphere is warm.
But the peculiar slant of the axis of the earth, together with the earth’s rotation, is not alone responsible for the change in seasons. That 66½° angle also gives us our five zones. On both sides of the equator we have the tropical zone, where the rays of the sun hit the surface of the earth either vertically or almost vertically. The northern and southern temperate zones are those regions between the tropics and the polar regions where the sun’s rays hit the earth a little less vertically and therefore have to warm a greater surface of soil or water than they do in the tropics. Until finally the two polar regions receive the rays of the sun at such an angle that even in summer each sixty-nine miles of sunlight is called upon to heat almost double that amount of land.
It is not easy to make these things clear on paper. There are great planetariums where you can see all this, and understand it too, in much less time than you need to read this. But these are few in number. Perhaps one of your friends may have an orrery, which is a small working model of the planetary system; if not, you may try your luck with oranges or apples and a candle and a little black ink to mark off the zones. A couple of matches will do for the North Pole and South Pole. And don’t indulge in comparisons when a fly descends upon your little home-made planet. Don’t say to yourself, “Suppose—just suppose—that we too should be only some sort of fly, crawling aimlessly across the surface of a gigantic orange, a gigantic orange illuminated by a gigantic candle—both of them little playthings in the hands of some colossus who wanted an afternoon’s entertainment!”
Imagination is a good thing.
But not in the realm of astronomy.
Chapter VI
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CONCERNING THE LITTLE SPOTS OF DRY LAND ON THIS PLANET, AND WHY SOME OF THEM ARE CALLED CONTINENTS AND OTHERS ARE NOT
All of us, without exception, live on islands. But some of these islands on our planet are so much larger than the others that we have decided to let them belong to a class of their own and have called them ‘continents.’ A continent, therefore, is an island which ‘contains’ or ‘holds together’ more territory than just an ordinary island like England or Madagascar or Manhattan.
But there are no hard and fast rules. America and Asia and Africa, being the biggest continuous pieces of land, are continents by right of their enormous size. Europe, which to the astronomers of the planet Mars undoubtedly looks like a peninsula of Asia (a little larger, perhaps, than India, but not very much), has always insisted on being a continent by itself. The Australians would undoubtedly be annoyed if anyone dared to suggest that their island was not really big enough and had not enough inhabitants to be ranked among the continents. The Greenlanders, on the other hand, seem quite contented to remain plain, ordinary Eskimos, although the country of their birth is half as large again as the combined area of New Guinea and Borneo, the two biggest islands on our planet; while the penguins of the South Pole, if they were not such humble and amiable creatures, might easily claim to be living on a continent, for the Antarctic region is larger than the land between the Arctic Sea and the Mediterranean.
I don’t know how all this confusion arose. But the science of geography passed through many centuries of absolute neglect.
During that period, erroneous notions attached themselves to the body of our geographical information as barnacles attach themselves to the keel of a ship that lies neglected in port. In the course of time (and the dark ages of our ignorance lasted about 1400 years) some of those masses of barnacles assumed such gigantic proportions that they were finally mistaken for parts of the ship.
ROCKALL—THE TOP OF A SUBMERGED CONTINENT IN THE NORTH ATLANTIC
But rather than add to the confusion, I will stick to the generally accepted divisions and I will say that there are five continents: Asia, America, Africa, Europe, and Australia, and that Asia is four and a half times as large as Europe, America four times as large, Africa three times, while Australia is a few hundred thousand square miles smaller. Asia and America and Africa therefore ought to be placed before Europe in a handbook on geography; but if we do not merely pay attention to size but also consider the rôle any given part of the world has played in the historical development of the entire planet, we must begin with Europe.
ARE OUR PROUD CONTINENTS PERHAPS ISLANDS OF SOME LIGHTER MATERIAL WHICH FLOAT UPON THE HEAVIER SUBSTANCE OF THE EARTH’S INTERIOR AS PIECES OF CORK WILL FLOAT ON WATER IN A BASIN?
Let us first look at the map. As a matter of feet, let us look at our maps oftener than we look at the printed page. For you might as well attempt to learn music without an instrument, or swimming without water, as to try to learn geography without a map. And as soon as you look at a map, or better still, if you can get hold of a globe, you will notice that the European peninsula, bounded by the Arctic Ocean and the Atlantic Ocean and the Mediterranean Sea, is situated right in the heart of that part of the world which contains the greatest amount of land, just as poor, neglected Australia happens to be situated in the centre of that other half of our planet which contains the greatest percentage of water. That was advantage number one which Europe enjoyed; but there were others. Asia might be about five times as large as Europe but while one-quarter of all its land is too hot for comfort, another quarter is situated in such close proximity to the North Pole that no one but a reindeer or a polar bear would choose it as a permanent place of residence.
There again Europe scored, for it enjoyed certain advantages which none of the other continents did. The toe of Italy, the southernmost point, although fairly warm, is still some 2600 miles removed from the equator. Northern Sweden, and Norway run quite a distance beyond the Polar circle, but it happens that the Gulf Stream visits their shores and keeps them warm, while Labrador, in an equal latitude, is a frozen wilderness.
Furthermore, Europe has a greater proportion of peninsulas and of gulfs, bays, and inlets than any other continent. Just think of the coastlines of Spain, Italy, Greece, Denmark, Scandinavia, think of the Baltic, the North Sea, the Mediterranean, the Aegean Sea, the Sea of Marmora, the Bay of Biscay, the Black Sea, and compare them with Africa or with South America, which have the lowest indented sea-boards. The result of such a large extent of water touching almost every part of the mainland is a very moderate climate. That means that the winters are not too cold and the summers are not too hot. Life is neither too easy nor too difficult, so that man becomes neither a loafer (as he does in Africa) nor a beast of burden (as he does in Asia) but is able to mix work and leisure in a more agreeable and useful proportion than anywhere else.
But it was not only the climate that, helped. Europeans to make themselves masters of the greater part of our planet. Their geological background was another point in their favour. This, of course, was a mere accident for which they deserve no personal credit. But just the same, they plucked the fruit of all those colossal volcanic eruptions and those gigantic glacial invasions and those catastrophic floods which had made their continent what it was, which had placed their mountains where they could most easily be turned into national frontiers, and which made their rivers flow in such a way that practically every part of the interior enjoyed direct communication with the sea, a most important point for the development of trade and commerce before the invention of the railway and the motor car.
The Pyrenees cut the Iberian peninsula off from the rest of Europe and became the natural frontier of Spain and Portugal. The Alps performed a similar service for Italy. The great plain of western France lay hidden behind the Cévennes, the Jura, and the Vosges mountains. The Carpathians acted as a bulwark which separated Hungary from the vast plains of Russia. The Austrian Empire, which played such an important part in the history of the last eight hundred years, consisted, roughly speaking, of a circular plain, surrounded by difficult mountain-ranges which protected it against its neighbours. Without these barriers Austria would never have existed so long as it did. Germany too was no mere political accident. It consisted of a large square of territory which sloped gently from the Alps and the mountains of Bohemia towards the Baltic Sea. And then there were islands, like England and those of the old Greek Aegean Sea, and swamps like Holland and Venice, ail of them natural fortresses which Providence itself seemed to have placed there for the development of independent political units.
Even Russia, which we so often hear described as the result of one man’s terrific desire for power (Peter the Great of the House of Romanov), was really much more the product of certain natural and inevitable causes than we are sometimes willing to believe. The great Russian plain, situated between the Arctic Ocean, the Caspian Sea, the Black Sea, and the Baltic, and between the Ural Mountains and the Carpathians, was ideally situated for the foundation of a highly centralized empire. The ease with which the United Soviet Republics went on ruling after the downfall of the Romanov dynasty seems to be conclusive proof of this.
MOUNTAINS AND SEAS MAKE EXCELLENT NATURAL BOUNDARIES
But the rivers, too, in Europe, as I have already remarked, ran in such a way that they could play a most important and practical part in the economic development of that continent. Draw a line from Madrid to Moscow, and you will notice that all the rivers, except the Danube, run either north or south, giving every part of the interior direct access to the sea. Since civilization has always been a product of water rather than land, this fortunate arrangement was of tremendous help in making Europe the richest and therefore the dominant centre of our planet until the disastrous and suicidal war of 1914–18 made her lose that enviable position. But let the maps bear me out.
Compare Europe with North America. On the latter continent two high mountain-ranges run almost parallel with the sea; and the entire middle part, the great central plain of the Middle West, has but one direct outlet to the sea, the Mississippi River and its tributaries, which run into the Gulf of Mexico, a sort of inland sea far removed from both the Atlantic and the Pacific Oceans. Or compare Europe with Asia, where a wrinkling process of the earth’s surface and the irregular slopes of all the mountain-ranges make the rivers run in any old direction, while the most important of those waterways, traversing the vast Siberian steppes, lose themselves in the Arctic Ocean and are of no earthly use to any one except a few local fishermen. Or with Australia, which has next to no navigable rivers. Or with Africa, a vast central plateau which forces the rivers to break through the high fringe of mountains near the coast and prevents sea traffic from using the natural waterways to reach the interior. Then you will begin to understand why Europe, with its convenient mountain-ranges and its even more convenient river systems, with four times as much coast-line as it would have if it were rounded off as neatly as Africa or Australia, with its moderate climate and its convenient situation right in the heart of the land masses of this earth, was predestined to play the part of the leading continent.
But those natural advantages alone would not have been enough to allow this tiny corner of the world to lord it over all its neighbours. The ingenuity of the inhabitants had to lend a hand. Their mathematics and their astronomy and trigonometry taught them how to sail the Seven Seas with a reasonable assurance of being able to return whence they had come. Their interest in chemistry provided them with an internal combustion machine (t
hat queer motor called a ‘gun’) by means of which they could kill other human beings and animals faster and more accurately than any other nation or tribe had ever been able to do. Their pursuit of medicine taught them how to make themselves comparatively immune against a variety of diseases which hitherto had kept whole regions of the earth in a state of chronic depopulation. And finally the comparative poverty of great tracts of their own soil (poor when compared to the plains of the Ganges or the mountain-ranges of Java) and the everlasting necessity of living rather ‘carefully’ had gradually developed such deep-seated habits of thrift and greed that Europeans would go to any extreme in order to acquire the wealth without which their neighbours regarded and scorned them as regrettable failures.
As soon as the introduction of that mysterious instrument known as the compass had made them independent of the church-tower and the familiar coast-line and allowed them to roam at will, and as soon as the rudder of the ship had been moved from the side to the stern (an improvement which seems to have occurred during the first half of the fourteenth century) the people of Europe were able to leave their little inland seas, the Mediterranean and the North Sea and the Baltic, and to make the gigantic Atlantic the highroad for their further exploits of a commercial and military character. Then at last they were able to make the fullest possible use of the fortunate incident which had placed their continent right in the heart of the greatest amount of land on our planet.
The Home of Mankind Page 6
