318. THE LAW OF EVOLUTION. 



of many members combined in many ways. And in them 

 we shall have to trace the transformation as displayed under 

 several forms — a passage of the total mass from a more dif- 

 fused to a more consolidated state; a concurrent similar 

 passage in every portion of it that comes to have a distin- 

 guishable individuality; and a simultaneous increase of 

 combination among such individuated portions. 



§ 108. Our Sidereal System by its general form, by its 

 clusters of stars of all degrees of closeness, and by its 

 nebulas in all stages of condensation, gives us grounds to 

 suspect that, generally and locally, concentration is going 

 on. Assume that its matter has been, and still is being, 

 drawn together by gravitation, and we have an explanation 

 of all its leading traits of structure — from its solidified 

 masses up to its collections of attenuated flocculi barely 

 discernible by the most powerful telescopes, from its double 

 stars up to such complex aggregates as the nubecula?. 

 Without dwelling on this evidence, however, let us pass to 

 the case of the Solar System. 



The belief, for which there are so many reasons, that this 

 has had a nebular genesis, is the belief that it has arisen by 

 the integration of matter and concomitant loss of motion. 

 Evolution, under its primary aspect, is illustrated most sim- 

 ply and clearly by this passage of the Solar System from 

 a widely diffused incoherent state to a consolidated coherent 

 state. "While, according to the nebular hypothesis, 



there has been going on this gradual concentration of the 

 Solar System as an aggregate, there has been a simultane- 

 ous concentration of each partially-independent member. 

 The substance of every planet in passing through its stages 

 of nebulous ring, gaseous spheroid, liquid spheroid, and 

 spheroid externally solidified, has in essentials paralleled the 

 changes gone through by the general mass; and every 

 satellite has done the like. Moreover, at the same 



time that the matter of the whole, as well as the matter of 



