ORGANIZATION OF THE SCIENCES 



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 surface, which we com- 

 monly call meteorology, and the general laws 

 of the formation of solid compounds, which we 

 call mineralogy, unite to furnish us with a gen- 

 eral doctrine of the massive and molecular mo- 

 tions going on at any given epoch and under 

 any given geographic condition of the earth's 

 surface. But geology has another clearly de- 

 fined 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 con- 

 sequent upon the relations between a cooling 

 rotating spheroid and a neighbouring sun which 

 imparts to it thermal, luminous, and actinic 

 undulations. This part of the science is already 

 currently known as Geogeny. And here we 

 touch upon the essential point of difference be- 

 tween geology and astronomy, regarded as sci- 

 ences 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 concerned with the 

 phenomena presented by a cooling and con- 

 tracting body, of the figure known as a spheroid 

 5 1 



