METEORS. 183 



the existence of life upon its surface) c many great and 

 small fragments, carrying seed, and living plants and 

 animals, will undoubtedly be scattered through space.* 

 Now, I venture directly to deny this proposition 

 that the earth will one day certainly come into col- 

 lision with another. It does not seem to me certain 

 even that, amid all the orbs which people the infinity 

 of space, there are two (tenanted by living creatures) 

 which will, even in the infinity of future time, be de- 

 stroyed by collision. It is absolutely certain that all 

 the primary orbs of our solar system are safe from 

 mutual collision or dangerous approach, either now or 

 at any future time ; so also the moons of Jupiter are 

 safe from collision or dangerous approach ; the moons 

 of Saturn equally safe ; and so also the moons of Uranus. 

 Now, so far as analogy can guide us, the suns which 

 form our galaxy must be regarded as equally safe from 

 mutual collision or dangerous approach. Simply by 

 virtue of their motions under the action of gravity, 

 they must be held judging from analogy to traverse 

 paths as free from mutual intersection as the paths of 

 the primary orbs of the solar system. If this is so, the 

 worlds over which any sun bears sway are as safe from 

 all risk of collisions with worlds belonging to the 

 domain of other suns as are the moons of Jupiter from 

 risk of collision with the moons of Saturn. It may well 

 be, or rather it is highly probable, so far as all known 

 analogies are concerned, that every risk of collision 

 between worlds belonging to different systems is thus 

 removed. But even if it were not so, if there really is 



