DISCOVERY 



25 



never be added to.' But can this quantity be reduced ? 

 That is the point, and the answer is that both its total 

 amount and, worse still, its available quantity can bo 

 vcrj^ seriously reduced in several ways. 



(i) A glacial period, for instance, would lock up 

 an immense quantity on the tops of the mountains, 

 and reduce the amount available for rains. 



(2) By chemical action a great deal of water is 

 withdrawn into vegetation and into the rocks forming 

 the substance of the earth. 



(3) It may be broken up into its constituent gases 

 and lost to the earth as water. 



(4) Water may sink into the earth farther than it 

 now goes and be out of reach of man and of the sun, 

 which now raises it up into clouds and distributes it 

 as rain. 



The most dangerous cause of reduction is the last. 

 It is admitted that the earth was once very hot, 

 spinning in space and surrounded with masses of 

 various vapours as Jupiter now is. As it chilled a 

 crust formed, on which water condensed when it was 

 cool enough. The seas collected in the hollows and, 

 being very hot, evaporated rapidly, causing torrential 

 rainfall which carved the surface into mountain, 

 valley, and plain. None of the water could penetrate 

 the surface, because it was so hot that it was driven 

 out as steam. Thus the whole of the moisture was on 

 the actual surface or in the clouds. 



As the earth cooled, water was able to penetrate 

 the surface more and more, following the heated core 

 as closel}' as the temperature would allow. The whole 

 crust is permeable, though not equally so. All rocks 

 and strata hold water to greater or less degree. It is 

 not possible to sink a deep shaft for a m.ine without 

 encountering water, as we know to our cost, for it 

 has to be pumped out at great expense. It is common 

 knowledge that, if a mine is not worked, it is soon 

 flooded. 



We are thus irresistibly forced to the conclusion 

 that we are in the midst of a gradual progressive 

 drying up of our earth, due to causes almost entirely 

 out of our control, which has already destroyed a 

 great deal of the best parts of the earth's surface and 

 now menaces the rest, and which must sooner or later 

 put an end to our race and all other life on the world. 



Wh.\t of the Future ? 



Though the world is drying up, mankind can probably 

 delay the process, if the nations will work together 

 to^this end. Our nearest planetary neighbour. Mars, 

 is apparently in worse case than we are, having reached 

 a more decrepit stage of stellar existence. There, 



' N.B. — The products of combustion appear to add water, 

 but really the actions of breathing and fire only cause the 

 return of what has been abstracted by the processes of life. 



according to Professors Schiapparelli, Lowell and 

 Pickering, life exists, but it is only made possible by 

 irrigation on a world-wide scale. Whether, when the 

 earth reaches this stage, there will be a struggle for 

 the water sources or not, is a problem that the future 

 only can solve. 



Reviews of Books 



SCIENCE AND PROGRESS 



Science and Human Affairs from the Viewpoint of Biology. 



By WiNTERTON C. Curtis, Ph.D., Professor of 



Zoology in the University of Missouri. (G. B;ll & 



Sons, 15s.) 

 Progress and Science. Essays in Criticism. By Robert 



Shafer. (Yale University Press, 125.) 



We live in a world to-day which is ruled by the great 

 god Science. Our very thoughts are dissected under its 

 laws ; we are born with all the resources of science to 

 expedite us, and die with all the resources of science to 

 delay us ; in the years between we are fed with food 

 rushed from the ends of the earth by the scientific control 

 of energy. We are in the very whirlpool of the scientific 

 age — from the day we first listen with amazement to the 

 ticking of an uncle's gold watch to the day when we observe 

 with anxious hope the last doctor's latest instrument. 

 We are face to face with an ever-widening vista of fact 

 and experiment and scientific theory which is bewildering 

 in its variety and utterly beyond our powers to grasp in 

 its entirety. 



And at times we ask ourselves certain questions. What 

 is progress, and how does science advance it ? What are 

 the great fundamental ideas underlying the scientist's 

 outlook to-day ? And, above all, how did all this marvel 

 of science begin, how did men live and think in the far- 

 away years, and what do we inherit from the remote past ? 



Professor Curtis's book provides us with answers to 

 all these questions. They are the answers of a man to 

 whom science is the aU-sufficient motive in life. He does 

 not consider very deeply whither humanity is bound ; 

 it suffices for him to know that we are slowly learning 

 what truth is. So the fairies and ghosts — and even, it 

 seems, Michael and all the angels — leave the dark nights 

 which once they haunted or made glad, and the stars and 

 the moon come into their own to provide an alternative 

 magic and poetry. He tells us how it all began — in Greece, 

 where man's unfettered mind first sought for great 

 unifying truths ; in Egypt, where mechanical invention 

 came to birth ; in Mesopotamia, where men learned to 

 deal with numbars and laid the foundations of mathematics. 

 There came the fall of ancient civilisation and the Dark 

 Ages as a flood to submerge all that had been won of fact 

 and theory and method over three thousand years. Pro- 

 fessor Curtis sees in the Middle Ages the crushing power 

 of authority in the form of the Church effectually sub- 



