THE DISTRIBUTION OF LAND AND WATER RELATIVE AREAS AND POSITION We have already noticed the characteristic irregularities of the earth's outer crust as regards elevation or relief. The same extreme irregularity is also apparent in the configura tion or contour of the land masses, a result of the irregular distribution of land and water. A careful examination of a map of the World or an artificial globe will show that the main element in this irregular distribution is the preponderance of land in the northern hemisphere ; and, vice versa, the vastly greater extent of water in the southern hemisphere. In round numbers, the actual and relative extent of land and water in the northern and southern hemispheres are as follows.
Were it necessary to illustrate this proportion by a map, we should have to take the north pole' as a centre for the northern hemisphere, and the south pole as a centre for the southern hemisphere, the radius in each case being 90° of latitude—the equator, of course, being the circumference. This arrangement not being frequently given in general atlases, the student would do well to construct a map of the world, showing the northern and southern hemispheres, for his own use.
The projection most commonly used in maps of the world is that of two hemispheres, the eastern and the western, the dividing line being a great circle drawn round the globe at a point W. long. This purely arbitrary division is nevertheless the most convenient for general purposes, show ing as it does the whole of the three continents of the Old World in the eastern, and the two continents of the New World in the western, hemisphere. The distribution of land and water, thus considered, is also very irregular, land pre dominating in the eastern, and water in the western, hemi sphere. In round numbers, the actual and relative areas are as follows.
But the irregularity of the distribution of land and water is, perhaps, most strikingly shown by projecting two hemispheres, the one having London for its centre, the other Antipodes Island. The former will be found to include all the great continental land masses, with the exception of a part of South America, Australia, and adjoining islands, and may therefore be called the continental) or land hemisphere, while the latter is nearly all occupied by water, and may be called the oceanic or water hemisphere. In round numbers,
the actual and relative areas of the continental and oceanic hemispheres are as follows.
Although London is not the actual centre of a hemi sphere that shall include the greatest possible proportion of the land of the globe—the exact centre being a point in the St George's Channel, midway between the English and Irish coasts—yet it is sufficiently near, that it may be considered as the centre of the whole habitable world. The geographical position of the metropolis as a centre, round which cluster all the great continents, marks it out as a centre of universal influence, and the empire of which it is the capital is indeed paramount in power, wealth, and influence—first in rank among the nations of the world.
If we consider the relative proportions of land and water in the different zones,' we find the largest area of land occurs in the North Temperate Zone.
relative areas of land and water in the different zones gives the following results Generally speaking, then, of a total superficial area of 197,000,000 square miles, about 51,500,000 are land, and 145,500,000 water—the former comprising one-fourth, the latter three fourths of the earth's surface. The most striking feature in this terraqueous arrangement, as we have already observed, is the predominance of land in the Northern, and of water in the Southern, Hemisphere. It will also be seen that the northern coasts of Europe, Asia, and America, almost encircle the north polar area, while the south polar regions are entirely surrounded by the vast expanse of the Southern Ocean. There are many other striking facts connected with the arrangement of land and water—such as the analogies and contrasts in form and disposition of the various land masses, &c. These we need not specify here, as the student can readily discover them on examination of a map of the world. We cannot, it is true, account for the present distribution of land and water—we only know that it is not the same as in former geological periods; for we have ample proofs that "con tinents existed where seas now roll, and seas extended where continents are now established."