24 Astronomy and Geology compared. PT. i. 



Here I propose to limit my comparison to the 

 Solar System. I will not venture to enter upon 

 those larger speculations which have been lately 

 opened by Professor Stokes and others in the field 

 of Sidereal Astronomy. I think it is sufficient for 

 my purpose to point out the vast disproportion in 

 size between the Earth and the other members of 

 our own system, and show that our world itself is 

 but a very small fraction of that great whole. When 

 we endeavour to pass beyond the limits of our own 

 system, we leave behind us our two great props and 

 aids the powers of the telescope and the resources 

 afforded by pure mathematics. Before these specu- 

 lations had been started, we possessed certain negative 

 testimonies with regard to the sidereal system lying 

 beyond our own. We knew that the range of our 

 own telescopes extended to the utmost limits of our 

 own system ; as therefore they were powerless when 

 applied to the fixed stars, it followed, as a natural 

 consequence, that the latter were greatly more re- 

 mote even than the most distant of our own planets. 

 We might also infer that, as the light of the Sun 

 can but feebly illuminate our own remoter planets, 

 it would produce no effect upon those still vaster 

 distances, and therefore that the fixed stars shine, 



