6 THE LESSON OF EVOLUTION 



However, slow as the process of condensation is, 

 it is not endless. In time all the meteoritic dust will 

 be collected into stars or planets ; and in time the 

 law of dissipation of energy will bring all these 

 bodies to a uniform temperature. It is the same 

 with gravitation. In time all the ponderable matter 

 in the Universe will either collect into a single mass, 

 or it will revolve round a common centre of gravity 

 which will be occupied by those portions of matter 

 which have come into collision during the process 

 of equilibration. 



So at last the movements due to the original 

 unequal distribution of matter will cease, and the 

 life of the Universe will come to an end. We know 

 of no process of rejuvenescence by means of which 

 dissipation of energy and the force of gravitation 

 might be counteracted. Several attempts have been 

 made to refute the theory of the dissipation of 

 energy, but all have failed. 



The ether, which pervades space, is the only part 

 of the Universe which shews no sign of evolution. 

 It alone is eternal. 



A casual glance at the stars gives us the impression 

 of immutability. We still speak of the " fixed 

 stars " in much the same way as our forefathers 

 used to speak of the " everlasting hills." But we 

 know that they are not fixed. We know that the 

 nearer stars, including the sun itself, are in s\\ift 

 movement ; and we infer that all are so. But we 

 can see no connection between their movements. 

 Single stars, or small groups of stars, are rushing 

 through space in various directions, and we cannot 



