74-(44) ABE OTHEE WOELDS INHABITED % 



of years ; man lias probably existed on it less than fcen 

 thousand years. Had an angel visited it at intervals of 

 ten thousand years, to seek for thinking beings, he would 

 have been disappointed a thousand times or more. Rea- 

 soning from analogy, we are led to believe that the same 

 disappointments might await him who should now travel 

 from planet to planet, and from system to system, on a 

 similar search.* 1 



This should end my discussion, but the advocates of 

 inhabitability reply : " Well, if the moon is not inhab- 

 ited now, it once was. True, it has neither air nor water, 

 but it once had, and at that time it had a teeming popula- 

 tion." When asked what evidence there is that the moon 

 once had an atmosphere and seas, they reply that the 

 moon, like the earth, has cooled down from a molten 

 condition, and that the earth is still cooling, and that 

 the time will come when it will have lost all its internal 

 heat, and that the attendant shrinkage will open vast 

 caverns, in its interior, into which both the air and the 

 water will descend, or perhaps, instead of vast caverns 

 being formed, the rocks will merely become porous ; in 

 either case, the air and water, will be absorbed. Then 

 some future astronomer in another planet, will describe 

 our earth as destitute of these essentials for living ani- 

 mals. The moon, they say, is now in that condition, 

 having, on account of its smaller size, run through its 

 cycle long ago, and is now cold and dead. 



At first glance, it may seem that no satisfactory reply 

 can be made to such an hypothesis. But there is an- 

 other science that has to do with world-building, the 

 science of geology. Its votaries have carefully studied 

 the effects of air and water and frost on the earth's sur- 

 face, and we are entitled to believe that if these ever ex- 

 isted in the moon, we should find traces of their work 

 corresponding to those which are found on the earth. 

 Geologists tell us that air, water and frost, are most 

 powerful agencies in disintegrating, tearing down, and 

 removing the hardest materials. Mountains have entire- 

 ly disappeared under their influence, and many thou- 

 sands of square miles of the earth's surface have been 

 stripped of the loose soil, and even the solid rock, to the 

 depth of many hundred feet. 



