METEORS. 169 



motions of meteors be correct, these bodies bring 

 before us, in the most direct possible manner, the 

 effects of this mighty force. They penetrate the 

 atmosphere of our earth with velocities generated 

 either by attracting bodies non-luminous stars for 

 instance other than those we are cognizant of, or else 

 by forms of force distinct from the attraction of gravity. 

 Here, then, we have a conception respecting these 

 bodies which is even more startling than the conception 

 that they may be fragments of an exploded world, or 

 that they may bear with them the germs of life. It is 

 true that we know of no instance in which a world has 

 exploded, for astronomers no longer imagine that the 

 asteroids are fragments of a world which once travelled 

 between the paths of Mars and Jupiter ; nor is it very 

 easy to conceive how the germs of living things can be 

 preserved under the conditions to which meteors are 

 subject. But volcanic action shows us at least how 

 worlds might be supposed to explode ; for we com- 

 monly compare a volcano to a safety-valve, and the 

 purpose of a safety-valve is to prevent explosion. And 

 again, the idea of the conveyance of the germs of life 

 from place to place is one with which we are sufficiently 

 familiar. But in the motions of the meteors we have 

 evidence either of the existence of bodies differing 

 from all with which we are acquainted, more massive 

 than the suns, but as opaque as the planets, or else 

 of the action of a force mightier than the force of 

 gravity. 



While we may admit, however, that in many in- 



