A.I ia. THE Mooy 397 



' supposed * fissures in the lunar crust^ 

 Cleave straight through the very ruggedest of mountains 

 and abhor the: Valleys ; for this is precisely what should be 

 expected of them. ; Nor is there any greater marvel in the 

 observed fact that such clefts and the pits of the deeper 

 craters actually delve down deep below the natural level 

 of the surface, thereby adding to the "cavernous" effects. 

 In terrestrial volcanoes the floor of the crater, far from 

 being deeper down than the -surrounding regions, is in- 

 vanriabiy much higher^-^t most 1 significant distinction, 

 9,1} 'lo mo j)od olofiv/ oil I .noon ii^iii JA .vfiu 'nwsii oiil io 

 tm) noil* bin* t v/t;;GENEBAC, BEIKDBCJIBIONS/, ;;a ai/ 



^^MN^^^^^M^iis. "^'inH^r 6* all^s^te} 

 of ^pti*y /Hnr stte. 1 ' i At kiMnigltf^dn; Me ! inooif ^hat Kttlei 

 air thfer^l^-^ouldlye jab^oTttteiy dr^'all of : its moisture 

 haraig 'been ; frozen out bf it? ^aiid deposited upon the sur- 

 face in the i6rin of frost ^,nil ! show. On the deepest beds 

 ?i ( the ^ sea 1 this ? (^vei^F^ofM be but a mere sprinkle, 

 having fallen after the des6eiit?of night a^ the last act in 

 th^yr^^bfpMay; 7 ; 



' ISf'o^, 'iin thp 'tnooii, 1 : byiiig to the exceedingly light 

 atniospheric pressure, water boils at a much lower teiri- 

 J>erature than here : let us say at 40 F., though this can 

 scarcely be more than a close guess. For this reason the 

 thawing process begins early -immediately with, or prob- 

 ably an hour before, dawn so that (as there is no light 

 refraction 1 there) pnfihe very lowest places such as the 

 mariaJto()fs^wUer\ tidies at its lightest, the snow may 

 Ipe effectually flooded oVer before observers can even 

 glimpse its presence. Granting the reasonableness of this 

 inference, it is easy to understand why areas seen to be 

 just wnitening" as they pass into the night may at their 

 succeeding dawn appear to have lost their whiteness from 

 some nocturnal cause^ instead of from the freshets caused 

 by the returning day. 



rn ^^^^^ff r tfsosfl^ j the lunar landscape, he first 

 shines upon the western sides of the hills; the eastern re- 

 u^mi^g^m : shadow, iUumijiated only by th^ reflection 

 from thevslopes opposite; Wherever his rays impinge, 



