THE MOON 347 



of the ring are conditioned in any way, or whether the 

 sizes of its component particles are minutely limited by a 

 natural law, or how such rings come into existence, or 

 how, in collapsing, they do so upon themselves instead of 

 upon their primary, or how they can collapse at all under 

 the Newtonian traditions. The exterior diameter of 

 Saturn's ring is only 173,000 miles, whereas the diameter 

 of the moon's orbit is 480,000 miles almost three times 

 as great ; nor is there any sign in his ring of any consid- 

 erable nucleus comparable in magnitude to our moon. 

 Should anyone suggest that the disintegration of such a 

 structure would result in the creation of another Saturn- 

 ian satellite instead of a meteoric shower upon that plan- 

 et, he would deservedly be looked upon askance. 



About the only characteristic marks on the moon's 

 surface that this impact theory even remotely fits is the 

 simple lunar crater, not all the craters, but only that sort 

 of crater that exhibits a small shallow pit without central 

 cones. It does not explain the depression of the pit 

 floors below the general level of the surface, or why some 

 of the craters biggest in diamter have quite low ramparts 

 and exhibit no inner depressions worth mentioning. It 

 does not explain the inner terraces, nor the non-destruc- 

 tion of the existing central cones, nor the strange coinci- 

 dence of groups of small craters huddled within the en- 

 closures of some of the larger ones. Nor does it explain 

 the remarkable phenomena of sugar-loaf mountains, the 

 stupendousness of the Apennine range, the strange im- 

 munity from petty bombardment of the vast areas called 

 maria, the wonderful chain of bluffs hemming in the 

 maria, the several-hundred-miles-long ravines, and the 

 like. Least of all does it account for the thousand and 

 one diurnal variations in the map and color of the moon, 

 of which, thanks to such keen and conscientious observers 

 as Professor Pickering, the recorded evidence is rapidly 

 accumulating since the first edition of this book ap- 

 peared. 



