Page:Popular Science Monthly Volume 53.djvu/113

Rh moist. Thus man's existence is dependent upon particular conditions of climate, the nature of the ground, and especially the relief—for the inequalities of relief, controlling the disposition of the water, exclude him from all those depressed parts which are submerged, and also from the highest spots that rise above the water.

The importance of the development attained by man in any region depends upon the same conditions. The wealth of a country must be derived from agriculture, manufactures, or commerce. Besides the factor of man's skill, it is the resultant of the natural conditions that favor the development of plants, animals, minerals, mechanical forces, and facility of communication; and all these are governed ultimately, as it would be easy to demonstrate by going into details, by these same conditions of climate, character of the ground or geological structure, and relief. When we come to consider the facilities of communication we find a new element entering into the consideration—that of situation. Even supposing that their resources are equal, we can not attribute the same value to two countries, one of which borders on civilized countries, while the other is in some out-of-the-way corner. Switzerland is worth more than Lapland, North America than South America, and Europe than Africa. A country well situated on the sea enjoys vastly greater advantages than a strictly inland country.

Of those who have treated the question of the factors constituting the value of a region of the earth, some have given pre-eminence to geological constitution, others to the relief, and others to the climate. None of these factors, it seems to me, can be regarded as exclusive, and none as always more important than the others. The favorable condition is a resultant to which all contribute. A thousand contrasts remain inexplicable if we presume that one of these factors prevails at the expense of the others. How shall we account for the dry soil of Beauce under the same amount of rainfall that once converted the adjoining Sologne into an impracticable and feverladen marsh, unless we regard the nature of the soil—compact and impenetrable in Sologne, permeable to excess in Beauce? How can we understand that the terrible deserts of Turkestan and the famous yellow lands of northern China, which bear such wonderful crops unmanured, are constituted of the same loess, unless we recollect that it rains regularly upon the loess regions of China, while those of Turkestan are baked under an ever-cloudless sky? And how, if we ignore the influence of climate, shall we explain that the high mountain and table lands, centers of repulsion in the temperate zones, become attractive under the equator? To attempt to explain such facts by a single essential condition would be to understand only part. In fact, all varieties of reliefs, ground structures, and