THE MOON 387 



Here you may interpose, "Then how do you account 

 for the fact that the same sort of thing hasn't happened 

 to the earth and Mars?" Easily enough. With respect 

 to the sun, the moon does not rotate on her axis in just the 

 same way as she does with respect to the earth, but turns 

 completely round, so that every point on her surface ex- 

 periences a day one of our fortnights long followed by a 

 night of equal length. In short, her days and nights are 

 virtually two seasons, summer and winter. This strange 

 arrangement, as you can see, accentuates many fold the 

 contrast between the seasons, and causes us to ruminate 

 how the thing works out. We have only to use our eyes 

 and brains to satisfy ourselves. 



By analogy, we are bound to presume that the moon 

 possesses, or at one time did possess, oceans in about the 

 same ratio to her mass as the earth, Mars and Venus. It 

 is true this is only a presumption ; nevertheless it places 

 the burden of proof on those who assert the opposite. 

 The question then confronts us : What effect should these 

 lunar changes of season naturally have on the waters of 

 her streams and oceans? That these would undergo 

 great evaporation under a steady stream of sunshine two 

 weeks on end goes without saying, even were the moon's 

 gravity as great as the earth's, a fortiori in that her 

 gravity is but 1-6 as strong. 



The question then arises : Would the seasons evenly 

 counterbalance each other, so that the summer's warmth 

 would completely counteract and undo the gelid effects 

 of the preceding winter! This question is not one for 

 argument, but for objective fact, and the moon's visibly 

 glacial condition is the answer. We have only to sup- 

 pose that at the beginning of the process, whenever that 

 may have been, the first winter deposited a greater litter 

 of snow than the ensuing summer succeeded in clear- 

 ing atvay, so that a residual sheet of snow how large is 

 immaterial, seeing that time was not of the essence re- 

 mained at the end of the first day (or summer) as the 

 nucleus for later accumulations to come. Thus, day by 

 day, with accelerated growth, the store of snow and ice 



