THE END OF THE MACHINE 461 



will cool. If there were planets revolving about it, a time 

 would come when life upon them would be impossible. The 

 image of the universe then would be that of an inert clod, 

 mindless, helpless, motionless, and dumb. 



All this, it scarce needs saying, is but the purest speculation. 

 Arrhenius, for example, has quite another view, offering, in his 

 textbook of cosmical physics, the idea that the matter of the 

 universe follows a continual round of alternating aggregation 

 and dispersion. The penetrating mind of this great Swedish 

 investigator conceives that this knows no end. In a private 

 note to the writer he very trenchantly observes : 



" Formerly we knew only of the Newtonian force of gravita- 

 tion, and therefore cherished the idea that in the end everything 

 would clump together. But we now know of the pressure of 

 radiation which may balance the tendency of congregation. At 

 the catastrophe of Nova Persei it was observed that hydrogen 

 shot out from "the star with a velocity of about 700 kilometres 

 per second. If Nova Persei is of the same magnitude as our 

 sun, this velocity is so great that it would drive the hydrogen 

 out from the gravitational field of the star into infinite space. 

 Many nebulae e.g. that of the Pleiades or Orion indicate by 

 their extraordinary dimensions such a diffusion into practically 

 infinite distances. 



" I therefore adhere to the idea of an oscillation of matter 

 because it is impossible for me to understand a beginning or an 

 end of the system of matter that we observe. If there were an 

 end, with complete rest, the condition would have been reached 

 in the infinity of time which lies behind us, and there would be 

 nothing left in the world for us to observe. Therefore also the 

 second law of thermo-dynamics cannot be perfectly true as it is 

 formulated now." 



The justice of these observations is evident. Yet it is difficult 

 to understand how the balance could be maintained simply from 

 the pressure of radiation without assumptions which as yet 

 have but a slight foundation. We might conceive, of course, 

 that the heat generated by the contraction of a nebulous mass 

 increases with the mass, and we might therefore imagine that 

 bodies enormously larger than our sun are likewise enormously 

 hotter. There is little, however, as yet, to suggest that such 

 is the case. The conclusions of Sir William Huggins, in fact, 

 are directly the contrary. He supposes that the maximum of 



