344 LAUGEL'S PKOBLEMS OF NATURE AND LIFE. 



already recognised, will so far answer the conditions 

 required as to be plausible in itself, and not to involve 

 any physical impossibility. Such element we venture 

 to believe may possibly be found in the ether of space ; 

 and as this hypothesis, though not wholly new to 

 science, has yet been only partially advocated, we must 

 ask to be allowed a few words in its illustration. 



Under the provisional name of Ether we recognise 

 in space around us, a medium capable of transmitting 

 the direct and reflected waves of light and heat, and 

 itself physically necessary for such transmission. While 

 forced to call this medium imponderable, its materiality 

 must be inferred from the very nature of the functions 

 it performs. Vast and complex though these be, we 

 cannot limit them to outer space only. We find full 

 evidence from optical and other phenomena that ether 

 interpenetrates and pervades the densest bodies on 

 which it pours its waves. May we not assume the fact 

 generally, that where it comes into contact with our 

 atmosphere and the grosser forms of terrestrial matter, 

 it assumes other conditions and properties than when 

 diffused equably and continuously through space ? Ke- 

 flected and refracted we know its waves to be. May 

 they not also be condensed, accumulated, evolved, 

 conducted in currents, and otherwise modified by the 

 kind of matter thus pervaded, and the changes this 

 undergoes from other causes acting upon it ? Without 

 assuming a knowledge we do not possess of the infini- 

 tesimal actions of the atoms and molecules of matter, 

 we may at least deem it certain that the agency of 

 ether, impinging upon and penetrating them, cannot be 



