Popular Science Monthly/Volume 53/May 1898/Man's Dependence on the Earth
|MAN'S DEPENDENCE ON THE EARTH.|
REGARDED in their relation to man, the different regions of the earth may be arranged under two general types. Some seem to repel man, who does not establish cities or large states in them. Their inhabitants lead a kind of vegetative existence, often as nomads, always thinly scattered, and poor if not wretched, with no aspirations beyond material existence. Other lands, on the contrary, seem to attract human life. Men flow to them from all quarters, as the blood from the extremities to the heart. They collect in opulent cities, and build up powerful states in which brilliant civilizations develop. But only a superficial glance over history is sufficient to enable us to recognize that these centers of resort and centers of dispersion change their places in the course of ages; and on every side we behold them undergoing alternations of grandeur and decay; countries once resplendent with glory are now deserted and wretched, while men are thronging toward regions which they formerly persistently avoided. The reason of these contrasts is to be found in the complex relation between the land and man. If man goes to one place in preference to another, it is because he finds there a fuller satisfaction of his desires and wants. To obtain the largest sum of enjoyment at the price of the smallest expenditure of effort is essentially a law of man's life. We may, therefore, conclude that if man turns away from a region to which he was once attracted it is because the resources of the country have become, in his eyes, relatively less valuable.
The study of the relations between man and the earth comprehends three parts: the determination of the factors on which the value of the relation depends; the variations of the relation and the inquiry whether it tends toward a limit, and, if so, toward what limit. The men who people the surface of the earth do not appear to have any great resemblance to one another, but the different races present very dissimilar physical characteristics and mental aptitudes. Yet these contrasts are purely superficial. At bottom all men are indifferently subjected to the same general conditions of existence and development. These conditions are of various kinds: some are essential in the nature of necessities that impose themselves on all animal life—such as the impossibility of subsisting without a certain quantity of air, warmth, and moisture, and vegetable or animal food; other conditions, still important but less essential, are those which, without directly influencing the very existence of man, favor or oppose his development. Nations are under similar conditions. As only a man whose corporal subsistence is assured can devote himself to research and the cultivation of thought, so only a rich nation can produce a remarkable literary or artistic movement. Civilization is the fruit of the leisure which material prosperity gives, and can not exist long of itself any more than a fire can continue to burn without being replenished. As a whole, the existence and development of man are subject to three series of conditions: for living, the realization of a certain minimum of indispensable natural requisites; for the creation of a particular civilization, a certain material abundance, which can be obtained only by utilizing the resources of the planet; and for the transformation of this local civilization into a general civilization, facilities for outside contact and mutual exchange.
The second term of this series is the earth, which is far from homogeneous in its different parts. Its surface is constituted of three elements of very different properties: a solid element, the land which incrusts the planetary spheroid; a fluid element, water, which occupies the cavities and depressions of the solid crust; and a gaseous element, the air, which envelops the land and the water. These elements, besides differing from one another, vary in their own qualities. Water is fresh or salt, stagnant or running; here spread out in wide, open oceans, there in interior basins or even confined in close ones; the air is warm or cold, moist or dry; and the solid crust is constituted of soils of different origin, composition, and aspect; level, moderately undulating, or bristling with mountains; formed of movable particles or of compact, hard masses.
The diversified shapes assumed by the constituent elements of our planet determine an infinite variety of aspects and resources. While the laws of human development remain the same everywhere, necessarily very unequal values attach to different regions in their relations to man. In fact, some parts of the earth are not at all adapted to human existence; others favor the development of a particular civilization; while other still more favored countries possess also the facilities for external communication indispensable for the growth of a brilliant civilization.
It is clearly evident that the earth does not furnish in all its parts even the minimum of. comforts necessary to human existence. Man can not live on the ocean except artificially and temporarily, and is consequently confined to the land. This is not adapted to the maintenance of man everywhere alike. In many places it only sparingly furnishes the food necessary to his life. In one place, as on the tops of high mountains, the air is too rarefied; at another, it is too cold or too arid, while in other places it is perniciously hot and 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 situations are found, in desert countries: mountain and plateau by the side of the plain; regions of primary rocks by the side of limestone formations, clays, sands, and lands of wholly different composition and age; hot and dry climates, and moist and cool; the sharp promontory looking out upon the open, and the gulf with low and swampy coast; and yet, also, among the countries that attract man, we can cite side by side the plain fruitful in harvest and the mountain rich in minerals; the temperate climates of the European seacoast and the hot and moist climate of the Soudan. The value of a country, therefore, does not depend upon any form of relief or any special situation or particular nature of the ground, or special climate, but upon all these things together and the way they are combined. Soil and climate affect fitness for agriculture; the geological formation bears on mining industry; relief, climate, and geological structure regulate the natural motor powers; and all these together, with situation, determine fitness for commercial enterprises. We may, therefore, define a country as the product of these four factors, either of which may, now here, now there, have the greater part in determining its production. If three of the factors are common to two countries, it only needs for the fourth to be different to determine a variance. Let one of these factors be eliminated, and the product becomes nothing. Such is the case in Greenland and desert countries generally, where the climate, a minor factor as to human existence in itself, produces a condition, however favorable the other factors may be, that makes human life almost impossible.
Thus in these four initial factors and their infinite combinations, under which the most numerous aspects and various conditions are engendered, are to be sought the reasons for the contrasts which are presented in the various regions of the earth and the human communities that are developed in them.
Both the earth and man are changing all the time, but there is no correspondence in the rate or the nature of the changes they undergo. The earth changes very slowly—so slowly that the progress is hardly appreciable in the lifetime of a single man, or so far, almost, of the human race; yet the continuance of its changes through a time of incalculable duration has made them very important, and has exposed it to many great revolutions.
Man undergoes vastly more rapid transformations. He is one of the latest comers on the earth, and has had an existence relatively as of only a moment. Yet he has undergone most wonderful transformations in his development from the cave dwellers of the stone age to the highly civilized man of the present, with his extensive knowledge and complicated relations. It is no exaggeration to say that the distance from the primitive man to the contemporary Englishman or Frenchman is not less than that from the rude marble block to the statue which the genius of an artist designs from it. So, while the earth has evolved slowly, man has developed with a feverish activity. With time he has contracted new needs and tastes, which have caused him to appreciate and seek out what he had despised; and, collected in groups, with gathered knowledge, men have acquired powerful forces which have enabled them finally to surmount obstacles that had at first stopped them. It could not be otherwise than that the value of the relation between the earth and man should have been frequently and materially modified.
Every one of the four factors of which we have determined the essential importance has undergone great variations in the course of man's evolution. Consider the relief. Hills and small mountains appear to have been the first places inhabited by man. It was in the foothills of the Pyrenees and the Alps, in the moderately elevated limestone plateaus of the central massif, and the modest heights of Charolais and Picardy, that were found the traces of the most ancient human occupation in France. It is reasonable that it should be so. The nascent brook, the living spring, the slightly undulating slope, are mollified natural forms with which the individual man can enter into immediate relation without exerting too great effort.
The plain, or rather the wet plain, offers only much later vestiges than the hills. Some may say it is because it has been dug over so often; but it is probable that life became possible in such situations only after some development of civilization. Regions subject to overflow and excess of stagnant water present obstacles to cultivation and comfortable living which it was beyond the power of primitive man to overcome, and would repel habitation for a long time. But once made habitable, the plain, with its mellow, fertile soil and its rivers offering easy ways of communication, would become attractive and draw population down from the hills, the chief value of which would henceforth lie in their adaptability to purposes of defense against attack.
Only the high mountain still remains unsubdued; but daily progress is made toward mastering it. Terrible in aspect, and seemingly beyond man's reach a hundred years ago, it is now the resort of tourists, and is climbed, traversed, and tunneled or threatened by railroads. It is not yet subdued, but it no longer stops us.
Thus each form of relief is more or less adapted to some of the many human wants. Each has its special value, changing from one epoch of civilization to another. The hill, an obstacle to the agriculturist and the merchant, has become auxiliary to the manufacturer through the motor force which is derived from its streams. The plain, precious in peaceful times, affords a poor shelter when war is raging.
So, also, the value of the different qualities of ground varies in different epochs. In the times when agricultural resources constituted the only or principal element of wealth, all the advantages appertained to lands in which the best qualities for tillage were combined. In the present age, the natural geological constitution of the soil is not of such paramount importance. As the earth has become better known, as scientific conditions of fertility have been ascertained through chemical analysis, man has learned to improve Nature by adding to soils the indispensable elements they did not already possess. Mechanical progress, creating increased facilities for transportation, and giving more perfect agricultural tools, has acted in the same direction. There is no soil so refractory that it may not be brought to reason by suitable application of fertilizing or corrective elements. By means of agricultural geology, which has been raised to a science, man can completely transform the natural value of any soil.
Different sorts of land have likewise values for mining not less unequal than their adaptations to agriculture. The minerals and coal with which industry is fed, and which have become the principal factors of wealth and power, have not been distributed at hazard over the globe. The beds exist in direct relation with the geological constitution. When we compare the fitness of different lands for mining and for agriculture, we most often find an incompatibility of qualities. The primary mineral and coal lands, when decomposed, yield chiefly hard gravels, cold and sterile. Secondary and Tertiary soils, on the other hand, almost destitute of minerals, most often have the looseness and the variety of composition that render them most friendly to remunerative cultivation. In view of these contrasts we are able to comprehend the importance of the revolution which modern scientific advance has provoked in causing preponderance of economical advantages to pass from agricultural fitness to adaptation to mineral and industrial exploitation. The equilibrium of the regions of the earth has been disturbed. Countries long neglected on account of their barrenness have been peopled all of a sudden because they contained coal; while other countries, which by virtue of their excellent agricultural soil had become chief centers of life, find themselves relegated to the second rank because that same rich agricultural soil affords nothing in the way of manufacturing facilities.
All climates, likewise, are not equally agreeable to man. Some are unhealthy, like those of marshy regions and equatorial countries, and hinder man's establishment within them, or condemn him to a precarious existence. Drainage, more and more extensively carried out, and the advance of hygienic science have modified and are still modifying these natural conditions; and the advance of civilization tends to diminish the difference in the specific value of climates to man.
As to the situation, man formerly, with his limited means, accommodated himself to Nature in the ways it offered. On the sea, he did not go far from the shores along which he coasted. On the land, he followed the stream, the valley, the mountain gorge, or the cove; and if the mountain stretched out in too compact a mass or presented a too high wall, rather than attack it in front he went round it. It is no longer so. Scientific advance has freed him from his close dependence upon these circumstances. The discovery of the compass brought on the advent of long sea voyages, and made possible the crossing of wide oceans. Moreover, we dig through continents to give passage to ships; attach islands to the mainland by means of gigantic viaducts; and pierce mountains by tunnels to give passage to railways. With each isthmus penetrated, each tunnel opened, and each new canal and railroad the courses of great commercial currents are turned. The road frequented yesterday is deserted to-day, and solitudes, lately unexplored, are filled with the periodical tumult of railway trains. Countries which were boasting of their situation deplore it now, as shops on a former principal thoroughfare in cities undergoing transformation are compelled to witness the diversion of movement and life away from them to new streets.
Thus the rational study of the soil as related to the successive scientific, historical, and social conditions of man gives the key to the local shiftings of civilization through the ages. It rested for a long time on the Mediterranean Sea, the peculiar situation and figure of which facilitated communication between bordering and adjacent countries, and this region was then the whole world, the sailor fancying when he got upon the ocean that he had passed the ends of the earth. The compass was discovered, sailors went farther, even to America, and the Atlantic Ocean became the center of the world; preponderance passed from the southern to the western countries of Europe. The development of steam navigation put all parts of the earth in constant communication. The Isthmus of Suez was pierced, and the Mediterranean recovered part of its lost prestige, while the Southern Atlantic ceased to be the principal route to the East Indies. Other changes, affecting the nations of western Europe, are still going on as results of these events; while in the extreme East, China, Japan, the Indies, and Australia, which were hardly known two hundred years ago, are forced into the current of western civilization. No one can predict what the end of this movement may be.
Without going into detail concerning the fluctuations seen in general history, we may consider those that have taken place in the interior development of particular countries. In France, once busy centers have declined, and their glory has been transferred to other places where conditions have in some way become more advantageous.
In the United States, a country as of yesterday, the fluctuations are sometimes very remarkable. A new region is opened to cultivation; a new lode is discovered; and railroads are built and cities rise as if by magic; then the railroad is extended, the mine is exhausted, or more fertile lands are discovered, and the new city disappears while another one is built somewhere else; but if the favorable conditions continue or others are found or made, it becomes permanent.
In England, the ancient towns which owed their prominence to military, ecclesiastical, or feudal conditions are declining or stationary, while places only recently of relative insignificance have become immense manufacturing centers or commercial cities.
There is no region which we can say will never be of importance; no country that can be supposed superior to a reverse of fortune. The most arid desert will become populous if a gold mine or a diamond bed is discovered in it; the most prosperous country would be liable to decline if a more important source of wealth were found near it. Suppose a method were discovered of applying the heat of the sun directly to the production of motion. Coal would become useless and coal lands waste. If a system of irrigation by artesian wells were practically developed and conveniently applied in the Great Desert, it would become populous. The future of any country is at the mercy of the discovery or of a new application by man of some property of matter. What seems to be a speculative research may possibly result in overthrowing the material or moral equilibrium of the world.
But while the evolution of the earth is going on slowly, almost imperceptibly to man, it is advancing all the time; and while man's evolution is, as we have seen, vastly more rapid to appearance, it has limitations. Man can never burst the bonds that subject him to Nature, and will never be able to abstract himself from the material necessities of his existence. Great as seem to be the resources now at his disposal, his development is absolutely controlled by the conditions of animal life. The earth is already far advanced on its course from the primitive nebulous condition toward that which has been reached by the moon. It, too, like the moon, will eventually lose its interior heat, its air and water will be absorbed into the rocks or will enter into new combinations. As man's existence was not possible under primitive conditions, so the time will come when the earth will no longer furnish him even a minimum of the necessaries of life. Even now life is not as exuberant as it was, although it is more varied.
The first care of a rational being whose resources are limited should be to husband them. Instead of doing this, we are spending lavishly, and seemingly wasting them all we can, and are destroying, without thought of the far future, the stores which the earth has laid up in the vast ages of the past. Even what we call improvement or development of a region is often its ultimate devastation, an improvident exploitation, removing from the earth what can not be restored to it, exhausting present supplies at the cost of the future. The grand discoveries on which we pride ourselves are often a contribution to this process, furnishing new means of expediting the waste and thus helping to bring on the final ruin.
Without indulging in too gloomy visions, it is a real truth that our exploitation of the earth's resources is pursued too recklessly. Consequently, we find that formerly fertile regions have become sterile; the productive deposits of our soils are undergoing exhaustion; the earth that should ripen our crops is allowed to flow into the rivers, making them turbid, and to be carried to the sea; fountains dry up, streams lose their way, and climates deteriorate.
The remedy by which these processes shall be prevented from ultimately making the planet unfit for habitation is to be found, instead of the present haphazard course, in applying rational and scientific methods in the exploitation of the earth's resources. The principle which, because it controls his development, man should never forget, is that he is a terrestrial being, that he is nothing without the earth, from which he can not disengage himself; and that the only true civilization is that which is developed in harmony and conformity with the laws that rule the planet.—Translated for the Popular Science Monthly from the Revue Scientifique.
- A paper read in the Congress of Scientific Societies, France.