WHY WE MAY ALL DIE OF THIRST.

Lake Wakatip Mail, Issue 2643, 28 August 1906, Page 7

WHY WE MAY ALL DIE OF THIRST.

* ALL WATER IS RAPIDLY DISAPPEARING FROM THE.FACE ->F THE EARTH. My Professor Garrett P. Serviss. Is the earth drying up and shall we (meaning by "via" the human race as represented by our descendants), die of thirst '.' A warning that this fate is n«-t impossible, or even improhabl \ seems to be conveyed bv some of the older worlds around us. The moon has become as dry as a bone, although the dark and empty beds of many seas and oceans are plainly visible upon its surface, showing that there was once a time when the lunar world possessed plenty of water. The planet Mars is more than half dried up. and now retains so little water that in the winter time it apl>ears to be all locked up in thr polar snows and ice fields, which are so thin that they quickly melt away when the summer sun shines hot niton them.

The planet Mercury apparently possesses no water at the present time, although, in the nature of tjiings. since it is composed of the same general elements as the other planetsit must have had water upon its surface at some past period in its history. Some think thai even Yenus is a dry. hot world, with little or no water available to support inhabitants. The observations of Prof. Lowell at any rate support this conclusion. From these examples we see that there is nothing essentially improbable in the idea that the waters of the earth may eventually disappear, leaving it as dry and barren us its near companion, the moon. But there is more direct and startling evidence of the drying up of the earth than any afforded by their analogies with other planets. This evidence is of a scientific nature, and we find it in the known disapjiearanee of many great bodies of water which existed on various parts of the globe in former times, and in the gradual. and in some cases, rapid, dessication of vast continental areas. Nothing more ominous could well be found than the proof afforded by recent scientific exploration of Central Asia that a large part of the greatest of the continents, the one which is believed to have contained the Garden of Eden and the cradle of mankind, has been turned into a waterless desert within the historic period ! CITIES LONG DEAD FROM THIRST.

East of the Caspian Sea and north ami west of the vast ranges of the Himalayan mountains, within a fewyears past the remains of large cities have been found, covered with drifting sands and choking dust which the dry winds whirl up in immense smothering clouds. Some of these vanished towns of Central Asia give evidence In their ruins that they once lay on the shores of lakes and rivers and other bodies of water which have since completely disapl>eared. Now they are only the dessicated skeletons of a civilisation whose founders either perished of thirst or were driven forth into moro favoured lands where the advancing aridity has not jet attained a fatal point. Central Asia is a lofty plateau, and it is on these higher levels of the earth that the disappearance of the water has everywhere been manifested. All the Asian deserts seem to be advancing their sandy frontiers on every side, and invading the surrounding lands which still retain, though in diminished measure their supply of life-giving water. The green borders are even where receding before the remorseless yellow wastes. The continent of Africa has long been undergoing a similar drying process. .There are in the midst of the Desert of Sahara plain evidences of the former existence of inhabited oases that were once green and flourishing with trees and smaller, vegetation, but which are now swept > by sand storms and destitute of the! least drop of water. One of the things that most powerfully impressed! the minds of the members of the \ British Association for the Advancement of Science during their visit to Africa last summer, was the lack of water over vast areas of that con-, tinent and the universal necessity; of irrigation to keep alive the lands that are yet in a habitable condition, The president of the engineering sec-! tion of the Association declared that ' it is a general condition of African j agriculture that the needed water I must be provided by human inter- j vention. Left to nature, many of i tie now inhabited parts of Africa! would f|uirkly be turned into lifeless! deserts. But the struggle can only J l.e maintained successfully as long • as the present supply of water capa-j Me of being turned into irrigating j ditches remains undiminished, and; the example of the fate that a part j of Central Asia has suffered indicates | that the time is sure to come wheuj the supply wHII be insufficient.

Many African lakes have disappeared in whole or in part within a lew generations. Lake Ngami, discovered by Livingstone, is no longer in existence : Lake Tchad, which occupied a conspicuous place on maps of Africa when many of the older readers of this newspaper were school children, has notw half' dried up. smaller bodies of water have completely vanished. The same story comes from Australia, from South America, and from parts of North America. The pieat Salt Lake in Utah is rapidly reding, like a puddle drying in the n. leaving nn ever-broadening nnruiii of white salt waste around us shrinking beaches. Some of the arid western lands which modern enterprise has begun to cultivate with the aid of irrigation wells and ditches, are known to have been once the bottoms of great lakes and seas. The process' whereby these waters have disappeared is a continuous one although its progress may be masked for a time by human effort. Yet man cannot make a water supply : he can only take what nature gives and distribute it in such a manner as may best suit his needs. Hut when Hi'- suppl.S fails he must give up his efforts. Through his own fault he often accelerates the dessicatitm of the land, for all o\er the world il has been demonstrated that destruction «»f forests brings about arid conditions. Even if the fortunate presence of mountain ranges tends to keep up the supply ol water for certain districts by condensing the moisture drifting in from the ocean and storing it up in glaciers and springs, and especially in the porous sponge-

like soli of great forests . yet the destruction orf the forests, and the denudation of the hill slopes defeats this kindly purpose of nature, causing the water in rainy seasons and during the melting of the mountain snows to rush down in destructive floods, which swiftly cross the lower lands without staying to moisten their soil, and hurry off to he lost in the sea.

Man cannot lift the ocean waters to freshen the continents : only the power of the sun can do that, and if, 1 by making smooth and clear its road back to the ocean he enables the water that has descended on the hills in the form of rain to hurry down again to sea-level, he loses all I the advantages that the sun has ofi fered him. and finds his farms drying I up and himself and his cattle threatj ened with a thirst that cannot be quenched. | THEN lIIE OCEANS WILL GO DRY. Let this process go on long enough and the earth will possess no more fresh water, except such as pours uselessly and destructively, down in the form of cloud-bursts and delugI ing rains. Then it will not be possible for the great populations of the I globe to find sustenance by hugging j the seashores. And in the end the j seas themselves will shrink and ultij niately disappear. But what, it may be asked, becomes of the water that has disappeared when lakes and rivers dry up? Much of it sinks into the earth's crust. The globe is hot within and is gradually cooling. As the interior cools crevices and cavities are formed and the surface water, seeking the lowest level under the force of gravition, penetrates to great depths. I'nderneath South Dakota and some of the other States bordering the Rocky Mountain region, it has been demonstrated that there is an I immense sheet of underground water 1 gradually making its way through the sandstones towards the Mississippi and the Gulf. At present some of this water can be reached and brought to the surface by means of artesian wells, but as the globe continues to cool the water will shrink lower and lower, until it gets too deep to be brought to the surface by human contrivance. And not only does the water of the earth tend to disappear by sinking into the crust and forming deep reservoirs and vast s+iects there, but much of it probably enters into chemical combination with the cooling rocks. In the case of the moon, where the cooling process, owing to the comparitively small dimensions

of the lunar globe, has gone on much more rapidly than in the earth, it is believed by many that the water formerly existing on the surf-ace as lakes, seas and rivers, has been completely absorbed by oxidation, the oxygen of the water combining with the metalliferous interior rocks. And the ultimate fate of the waters of the earth may be similar. WATER SINKS INTO THE EARTH In fact the whole history of our planet, as geology has disclosed it. is such as to lead to the conclusion that its surface must eventually be- j come a dry and barren waste. At first a molten globe the earth cooled down until it had a crust of solid j rock. On this crust, as it in turn | cooled off, the vapors of the atmns- j phere descended and condensed into I oceans. Some have thought that in j the beginning the entire earth was covered with water, but as the cool-; ing of the glnbe continued much of: the water constituting the primeval ocean was absorbed into the deepen-I ing crust. Then continents made their appearance and then gradually became more extensive. But in the earliest period at which geology has ; ventured to draw a chart of the earth, we see that the proportion oil land to water was very much less than it is to-day. (iradually the dessication has pro-; reeded, and apparently it is destined j to go on until even the Atlantic and! the Pacific have disappeared, and all the waters of the earth are with-; drawn into its interior or destroyed by chemical dissociation of the liquid i and the recombination of its elements with solid matter. Long before that stage is attained, however, all animal and vegetable life will have disappeared from the lands. for they cannot survive the withdrawal of the fresh water upon which their existence depands. The salt oceans, becoming ever more salt as their volume shrinks, may at last reach a point of concentration where even marine life will be destroyed.

Thus the last picture of the earth that geology can form by glancing into the future shows it stripped of its inhabitants and of all forms of life, and deprived of water and perhaps also of atrnosphere—a bare wreck of a planet, drifting in the ethereal ocean of immensity.—"NewYork American Journal."