220 COSMIC PHILOSOPHY, [ft. i. 



It remains to add that each of the five concrete sciences 

 may, for the purposes of our philosophic synthesis, be advan- 

 tageously regarded as consisting of two portions. In the 

 first place, we have Astronomy — in the time-honoured sense 

 of the word — which deals with the motions of stellar and 

 planetary masses in their present state of moving equili- 

 brium ; and Astrogeny, as it is now frequently termed, which 

 seeks to ascertain the genesis of these masses and of their 

 motions. 



Geology admits of a similar division. The general laws of 

 the •redistribution of gases and liquids over the earth's sur- 

 face, which we commonly call meteorology, and the general 

 laws of the formation of solid compounds, which we call 

 mineralogy, unite to furnish us with a general doctrine of the 

 massive and molecular motions going on at any given epoch 

 and under any given geographic condition of the earth's sur- 

 face. But geology has another clearly-defined province ; 

 which is to formulate the general order of sequence among 

 terrestrial epochs ; to ascertain the genesis of the various 

 molar and molecular redistributions going on at any given 

 period, by regarding them as consequent upon the relations 

 between a cooling rotating spheroid and a neighbouring sun 

 which imparts to it thermal, luminous, and actinic undula- 

 tions. This part of the science is already currently known 

 as Geogeny. And here we touch upon the essential point of 

 difference between geology and astronomy, regarded as 

 sciences of development, which it seems to me that M. 

 Wyrouboff, in his interesting essay upon this subject, has 

 quite lost sight of. Both astrogeny and geogeny are con- 

 cerned with the phenomena presented by a cooling and con- 

 tracting body, of the figure known as a spheroid of rotation. 

 In the one case this body is the sun, which once more than 

 filled the orbit of Neptune ; in the other case it is the earth, 

 which at first more than filled the moon's orbit. But together 

 with this point of community between the two sciences, there 



