CHAPTEK III. 



THE NATUEAL HISTOEY OF THE SOLAE SYSTEM ANA- 

 LOGICALLY EETEACED. 



ADMITTING that the foregoing hypothesis as to the original 

 condition of the earth's materials has any foundation in truth, 

 we find in it the link which connects geology with astronomy. 

 It must be borne in mind that the earth is only one member 

 of the great family of planets belonging to the solar system ; 

 and it is fair to presume that the brothers and sisters of the 

 same planetary family have the same, or a similar, origin 

 especially as they have the same oblately spheroidal form, 

 and observe the same laws of diurnal and orbitual revolution. 

 If the earth, then, was originally in a state of igneous gas, so 

 (we may suppose) were fkey ; and before the incipient pro- 

 cesses of spheroidation commenced, the materials of all of 

 them may have commingled, and probably did commingle, 

 together in one undistinguishable mass. 



Though this hypothesis of an original gaseous state of the 

 earth and planets rests upon a foundation of its own (being a 

 portion of the chain of analogous developments prolonged 

 directly backward from the links of substantial geological 

 facts), it is precisely in accordance with the nebular theory of 

 the origin of worlds and systems, which theory also rests upon 

 independent grounds of reasoning. As a conviction of the 

 general truthfulness of this theory is important as a basis of 

 ulterior ideas to be presented in this treatise, the patient 



