DIASTROPHISM AND THE FORMATIVE PROCESSES 



17 



would seem to mean that the porosity of the moon is represented by 

 35 miles in terms of radius, over and above such compression as its 

 center has suffered. This may be taken tentatively as representing 

 the deep porosity of the moon. Similarly, the porosity of Mars 

 would be represented by 22 miles in excess of its central com- 

 pression. On the other hand, the actual compression of Venus 

 seems to be represented by 367 miles, while the corresponding 

 figure for the earth is 572 miles. 



TABLE III 



Comparison of Meteorite-Parity with Actual Bodies 



In the fifth column the degrees of compression are reduced to a 

 common unit-mass. This brings out the essence of the matter in a 

 striking way. It appears that the moon, built up as it actually was, 

 failed to compress itself to the meteorite standard by 28.7 miles 

 per unit of mass-growth, and Mars by 2.0 miles per unit, while 

 Venus compressed itself beyond the meteorite standard to the 

 extent of 4.5 miles per unit of mass-growth, and the earth by 

 5 . 7 miles per unit. This seems to put the first two bodies in one 

 category and the last two in quite another category, while it greatly 

 emphasizes the progressive nature of the compression from the 

 least to the greatest, even per unit-mass of increase. 



Let us, however, hold all these tentative results in abeyance 

 until we have more critically considered the probabihties in respect 

 to the inherent nature of the material that entered into the con- 

 stitution of these four bodies. Meanwhile this preliminary in- 

 spection may serve to give point to the study of the genetic con- 

 ditions that affected these results. This study will be the theme 

 of the succeeding article. 



