COSMIC PHILOSOPHY 



tracting bodies evolve heat, and that radiating 

 bodies contract. 



Obviously, therefore, if we were to go back 

 far enough, we should find the earth filling the 

 moon's orbit, 1 so that the matter now compos- 

 ing the moon would then have formed a part 

 of the equatorial zone of the earth. At a period 

 still more remote, the earth itself must have 

 formed a tiny portion of the equatorial zone of 

 the sun, which then filled the earth's orbit. At 

 a still earlier date, the entire solar system must 

 have consisted simply of the sun, which, more 

 than filling Neptune's orbit, must have consisted 

 of diffused vaporous matter, like that of which 

 the irresolvable nebulae have recently been 

 proved to consist. Now in the slow concentra- 

 tion of the matter constituting this solar neb- 

 ula, as both Kant and Laplace have elaborately 

 proved, the most prominent peculiarities of the 

 solar system find their complete explanation. 

 Supposing the sun to have been once a mass of 

 nebulous vapour, extending in every direction 

 far beyond the present limits of the solar sys- 



1 It is not presumed, however, that the moon's orbit was 

 originally so large as at present. For by its tidal action upon 

 our oceans the moon exerts a drag upon the earth's rotation, 

 and the motion thus lost by the earth is added to the moon's 

 tangential momentum, thus increasing the dimensions of its 

 orbit. A precisely similar qualification is needed for the two 

 next succeeding statements in the text. 



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