342 FROM NEBULA TO NEBULA 



smgle crater or, in fact, any protuberant irregularity at 

 all has yet been descried upon his surface! Judging 

 from these two bodies, Mars and the moon, alone, then, 

 we should naturally conclude that the smaller the cosmic 

 body the more rugged. But proceeding another step 

 higher, we find this rule already violated ; for the earth is 

 very much rougher than Mars, yet far less so than our 

 satellite. Now, inasmuch as our Vulcanists are uni- 

 versally agreed in holding that our planet, too, is a 

 shrinking body and that the asperities on her surface 

 are due solely to this cause and the kindred cause of vol- 

 canic upheaval, it follows that the only salvation for the 

 Volcanic hypothesis is to establish that the moon, when 

 she gained her supposed separate existence, must have 

 been far hotter than Mars and at least as hot as the 

 parturient earth. In fine, the Vulcanists are logically 

 forced to be Tidal-evolutionists, and their theory conse- 

 quently rests on Darwin's admittedly "wild speculation 

 impossible of verification". 



Secondly, investigation has shown that the earth's 

 temperature rises one degree for every sixty feet of 

 depth, and it is only fair to presume that this rule held 

 relatively true throughout her postulated contracting 

 process. Judging by the existing gradient, the tempera- 

 ture at the earth's center should be about 320,000 degrees 

 F. as against, say, 550, absolute, near the surface. If, 

 now, we conceive the earth to be divided into 81 concen- 

 tric strata, all of them of equal mass, the temperature of 

 the outermost should average only that degree marking 

 the middle of its thickness, or, by calculation, 1250 F., 

 abs., while the average temperature for the entire planet 

 should be no less than 80,000 degrees! Now, Darwin's 

 idea was not that the moon was explosively ejected out of 

 the heart of the earth, but that she was flung off from its 

 periphery by centrifugal force. Had the former act been 

 postulated, it would be good logic to say that she bore 

 with her the average temperature of the planet, but inas- 

 much as she was flung off from the outside, her hotness 

 could not have been greater than that of the crust, the 

 very coldest part of the planet, and theoretically very 



