Contrast of the Land and Water Hemispheres.
Whether we divide the globe into northern and southern or eastern and western hemispheres, their relative amounts of land and water will be different The northern hemisphere contains (speaking approximatively as above) 38,541,600 square miles of land, and 59,619,700 of water; the southern, 12,847,200 of land, and 85,526,100 of water. The eastern hemisphere contains 36,760,800 square miles of land, and 61,401,000 of water; the western, 14,628,000 of land, and 83,533,300 of water.
Besides the division quantitatively, the division in respect to symmetry of shape is entirely irregular. Symmetry, as we usually use the word, consists in the arrangement of parts at equal distances, or two sides at least, from some central point or line. Mineral crystals are regarded in relation to the point where crystallization began; plants are viewed in relation to the stem-axis; animals in relation to the symmetry of the entire structure. A similar law of symmetry is entirely wanting to the globe; its arrangement is altogether unlike this; it is not nearly so perceptible at first glance, yet it is far more profound in design and comprehensive in its relations.
The land is broken up into masses, varying in size, and called, arbitrarily, continents and islands. Strictly speaking, there are but two continents, the old world forming one, the new world the other. Australia may be called the smallest continent or the largest island; it is the connecting link between the forms, and shows at a glance the arbitrary distinction. We might easily go further and call New Guinea, Borneo, Sumatra, Great Britain, and Java, continents, and, on the other hand, we might designate the old and the new world as islands. There is nothing absolute here but the usage of speech.
The continents and islands lie mainly in the northern hemisphere, (38,341,600 square miles,) scarcely a third part of their superficies (12,847,200 square miles) being in the southern.
The continents are so situated also that the eastern contains by far the largest body of land, (36,760,800 square miles,) the western being only about one-third as large, (13,628,000 square miles.) America, the western, it will be seen, has no first-class island lying near it; it stands isolated.
It is seen by this that the greatest mass of land lies in the northern hemisphere, dividing the earth in one way, and in the eastern dividing it in another; the smallest mass in the southern and the western. In the northeast the watery realm is the most contracted, in the southwest the least. We are thus enabled to speak of the land side of the globe, the land hemisphere, and a water side, the water hemisphere.
The central point of the water hemisphere is at the island of New Zealand. Toward this the points of all the continents are directed. The center of the land hemisphere is in the northwest of Europe, at a point near southeast of England, the northeast of France, and the coast of Holland. The dwellers around the North Sea are the antipodes of the New Zealanders. Great Britain is the country which, as a whole, is the middle point of the continental world. In the oceanic world, the islands lie like scattered dots, insignificant in respect to area, in comparison with the waste of waters which surrounds them, while, on the other hand, the land hemisphere is so solidly compacted, that even the Arctic Ocean becomes merely a broad channel.
Thus arises the first great contrast which we have to study: the first, and next to the great primary distinction between the North and South, the most important. The division into land and water, aside from commerce, must exercise the strongest influence on the distribution of heat and cold, affecting the temperature of all the zones. This influence has been fully noticed and brought before the world by Alexander von Humboldt. It is sufficient to refer to it now as a well-determined fact in physical geography.
The heat equator is a little farther north than the mathematical equator, because the land hemisphere has a greater heat capacity (if we may use an awkward but apt word) than the water hemisphere. All other isothermal lines are modified in their greater or less coincidence with the parallels of latitude as they advance from the heat equator toward the maximum of the land hemisphere, or, in general terms, as they go northward. In the western hemisphere the isothermal lines follow much more exactly the parallels of latitude than in the eastern, which is pre-eminently the land hemisphere. In America the proximity of immense masses of water causes a perceptible reduction of the heat from that of the eastern where the land form prevails. And the heat diminishes more as we advance toward the South Pole, than toward the North, in consequence of the greater deficiency of land in the southern hemisphere; while in Lapland, Greenland, and in Siberia, even within the polar circle itself, men find sustenance and trees live, in the same latitude, at the South Pole, no vegetable life, worth mentioning, is found. The frigid zone and the temperate zone of the southern hemisphere are not coincident with those of the northern. The icebergs which are formed at the South Pole are carried much nearer to the equator than those found at the North Pole.
An important phenomenon, first pointed out by A. von Humboldt and Dove, is closely connected with what has just been said. The Atlantic shores of the old world are warmer than those in the same latitude of the new world. Norway, England, and France are warmer than Labrador and Canada; Spain, Portugal, and Morocco are warmer than Florida; Congo and Benguela are warmer than Brazil, although the countries brought in contrast all lie on the same parallel.
A similar analogy is drawn from the west shore of America: Northern California is warmer than Japan and Corea, which are in the same latitude. It is true, other factors are at work to produce this, such as winds, marine currents, elevations of land, etc., of which more will be said hereafter.
Both of the two great land divisions of the earth, it will thus be seen, have their peculiarities. But there is a great equalizer of their diversities, found in a great coast-belt, of which I must briefly speak. It passes from the Cape of Good Hope northeasterly at an angle of 45°, passing through the Mozambique channel, thence skirting the entire southeastern and eastern coast of Asia, taking in China, Corea, Japan, and South Kamtckatka; thence it turns southward, following the whole western shore of America to Cape Horn. This belt is broken at only two points—a brief break at the north, at Behring’s Straits, and a large one between Cape Horn and the Cape of Good Hope; in other words, at the points nearest to the North and the South Poles respectively. This coast belt has a relation to the habitable world similar to that held by the temperate zone as a mediator between the torrid and the frigid. It partakes of the character of the sea and the land, and shows the advantages of both. It does not run parallel with the lines of latitude, but crosses them diagonally, in the same direction with the ecliptic, though at a more acute angle. This belt moderates all extremes. Coincident with it are the paths of the sea and land winds, the course of the monsoons, the most fertile shores of the whole globe. It divides the surface of the globe into three great divisions, the two great bodies of water, and the great, and, comparatively speaking, unbroken (for the break at Behring’s Straits is of little importance) land-mass. On the great coast line referred to above is the center of the great natural acclivities of the globe. It is the most varied, the most stimulating, and the most productive in all departments of the vegetable and animal kingdoms. The Atlantic coast belt, which also has great influence on the eastern districts of the new world and the western districts of the old, crosses the great coast belt at almost right angles at the place of its great sundering between Cape Horn and the Cape of Good Hope.
If the contrast between the sea and the land has the effect indicated above on the general development of organic life, it must of course have great effect also on the life and character of man. Man eminently depends upon the conditions amid which his lot is cast. The inhabitant of one of the Pacific islands dwelt in a world whose utmost possibilities to him lay in the adjacent islands within view, and which his canoe could reach in a few hours’ sail. The difference in culture between him and those whose range of observation has been greater, must be immense. The compacted land division of the globe, the solid cluster of continents, must be the source of stimulus and culture, of which the isolated inhabitant of the Pacific islands knew nothing, till commerce had at length linked the world together. Only with the improvements in navigation could civilization reach him. The European had to carry his culture to the New Zealander, his antipode.
The ancients had little suspicion of all this. Yet the contrast between the land world and the water world did not escape Strabo’s keen glances, and he hints at its effects on man. It is glanced at in one passage of his 15th Book. He is speaking of the effect of the moist air of India in contrast with the dry air of Libya, and shows that he appreciates that these are not without their influence on the constitution of the Indian and of the Ethiopian. “Some,” he says, “rightly ascribe it to the sun, that, in the absence of moisture in their air, the rays burn so deeply into the body of the African; the Indian, on the other hand, is not jet black and curly-haired, because, in his country, he enjoys the moisture in the atmosphere.”