FRAGMENTS OF SCIENCE. 



CHAPTER I. 



THE CONSTITUTION OF NATURE.* 



WE CANNOT think of space as finite, for wherever 

 in imagination we erect a boundary, we are compelled 

 to think of space as existing beyond it. Thus by 

 the incessant dissolution of limits we arrive at a more 

 or less adequate idea of the infinity of space. But though 

 compelled to think of space as unbounded, there is no 

 mental necessity compelling us to think of it either as filled 

 or empty; whether it is so or not must be decided by ex- 

 periment and observation. That it is not entirely void 

 the starry heavens declare; but the question still remains, 

 are the stars themselves hung in vacuo? Are the vast 

 regions which surround them, and across which their light 

 is propagated, absolutely empty? A century ago the 

 answer to this question, founded on the Newtonian theory, 

 would have been, " No, for particles of light are inces- 

 santly shot through space." The reply of modern science 

 is also negative, but on different grounds. It has the best 

 possible reasons for rejecting the idea of luminiferous 

 particles; but in support of the conclusion that the celes- 

 tial spaces are occupied by matter, it is able to offer proofs 

 almost as cogent as those which can be adduced of tho 

 existence of an atmosphere round the earth. Men's 

 minds, indeed, rose to a conception of the celestial and uni- 

 versal atmosphere through the study of the terrestrial 

 and local one. From the phenomena of sound, as dis- 

 played in the air, they ascended to the phenomena of 

 light, as displayed in-the ether; which is the name given to 

 the interstellar medium. 



The notion of this medium must not be considered as a 



* " Fortnightly Review," 1865, vol. iii. p. 129. 



