THE DISSOCIATION OF CHEMICAL ATOMS. 1 89 



§ 12. As to the manner of this evolution, Mr. 

 Crookes' suggestion rests on astronomical facts. 

 He infers from the fact that stars are not of all 

 sizes, but seem to vary within certain limits, that 

 there must be some agency to prevent the accretion 

 of the stars beyond a certain point. He also infers 

 from the fact that compound bodies are dissociated 

 by heat, that the '' elements," if compound, must 

 also be dissociated at very high temperatures. 

 Hence he supposes that in the centre of the hottest 

 stars all elements are dissociated. But dissociated 

 into what ? Into that out of which they were all 

 evolved, says Mr. Crookes, i.e., into prothyle, the 

 undifferentiated basis of chemical evolution, the 

 formless stuff which was the origin of all substances. 

 And so, while from our point of view matter simply 

 disappears at the centres- of the hottest stars, when 

 the temperature exceeds a certain point, it is really 

 reconverted into prothyle, which does not gravitate, 

 because it is anterior to the differentiation of gravi- 

 tating matter and imponderable ether. But though 

 (sensible) matter is thus apparently destroyed at the 

 centres of the universe, this loss is compensated by 

 the genesis of matter at its canfines. The existence 

 of limits to space Mr. Crookes supports by an in- 

 genious calculation, that " if an unlimited world of 

 stars sent us radiations, we should receive 200,000 

 times as much light and heat as we do receive, 

 unless radiations are absorbed or intercepted to 

 such an extent that only ^^^ reaches us. This Is 

 so improbable that the conclusion that the universe 

 is limited is with some emphasis declared by 

 astronomy." ^ And there is the less reason to object 



1 V. Mr. J. G. Stoney's letter to the Tirrm (4th April, 1888), in 

 support of Mr. Crookes' speculations. 



