Читать книгу The Romance of Modern Geology. Describing in simple but exact language the making of the earth with some account of prehistoric animal life онлайн

14 страница из 54

That is, on the whole, a reasonable answer. But apply the same reasoning to the question of where the waters of the earth in the shape of oceans ought to lie as they cling to the spinning globe. They cling to the globe, not because they are sticky, but because of the attraction which we say is due to gravity—the force which makes everything in nature attract every other thing, and which makes everything tend to fall to the earth (and to stay there). They do so because the earth, being so very heavy and bulky in comparison with anything in its neighbourhood, has such an enormous pull. How great that pull is may be dimly gathered from the reflection that though the earth is spinning at the rate of a thousand miles an hour, nothing is ever shaken off. The oceans are not shaken off. They cling. But why is it that they are not equally distributed all over the face of the earth? If a map of the earth be examined, or still better a globe with the oceans and continents correctly drawn on it, it will be found that there is a great mass of land all lying grouped together on one side of the earth, and a great basin of waters on the other. Let the reader imagine himself a thousand miles above the earth, looking down at a point in it about midway between Madeira and the Bermudas. What would he see? He would see the Atlantic Ocean, but all around it would be grouped great masses of land—Europe, Africa, North America, Asia—and if it were his first sight of the earth and he knew nothing of its geography, he would be likely to suppose that the earth was nearly all land, with one comparatively small stretch of unfrozen ocean. But now let the reader move round the earth to a point exactly opposite that at which he took his first observations and look down again. He will now see the Australian continent and the land which covers the South Pole, but except for the pointed tail of South America, and perhaps a glimpse of the blunter point of South Africa, he will be looking down on a globe which seems to be largely covered with water.