350 FKOM NEBULA TO NEBULA 



of white flakes, which, settling on the dry surfaces, have 

 made these their permanent abode. Owing to the ge- 

 ometrical fact that the areas of small spheres are, rela- 

 tively to their mass, larger than in larger spheres, the 

 oceans of the moon were proportionally shallower, aver- 

 aging, in fact, only about a half mile in depth. As the 

 levels in these receded because of the snow exodus, 

 naturally the protuberances (of uneven height) on the 

 bottom became successively exposed with lapse of time, 

 creating new islands and new resting places for the flakes. 

 Now, it is self-evident that the nearer the pinnacles of 

 these originally submerged protuberances lay to the sur- 

 face of the sea, the sooner would they have become ex- 

 posed and the sooner would the flakes begin building up- 

 on them; but it is also true that, unlike on land surfaces, 

 such sub-aqueous irregularities are the exception rather 

 than the rule, hence snow mounds on the sea-beds should 

 not only be lesser in magnitude, but fewer in number. 



Inasmuch as, according to our premiss, there was 

 never a let-up to this peculiar process of ocean-robbing, 

 the time eventually arrived when the entire floor became 

 virtually uncovered, presenting in reality a land scene in 

 which every bar and sink-hole showed save, however, 

 that on all the emerged spots there rested columns of 

 snow, more or less squat, and that the sink-holes were 

 normally empty. I say normally empty advisedly, for 

 the reason that during the hot season, as we can see to- 

 day, a good deal of the snow naturally thaws again and 

 trickles down into the lowest places, forming there black 

 pools which contrast vividly with the scant vestiges of 

 snow that may be found in these recurrently flooded re- 

 gions. Between the blackness of such pools, however, 

 and driven snow, there are, of course, all gradations of 

 white though no colors to be seen. These diverse 

 shades are due to one, or to the combination, of two 

 causes ; first, to the soaking of low-lying snow as a result 

 of thawing, and, second, to a seaming and corrugating of 

 other snow surfaces, especially on slopes, by irregular 

 thawing, slipping, and settling ; the dense shadows of the 

 ridges in the furrows marring the general brightness. 



