354 POPULAR SCIENCE MONTHLY. 



it. We have no evidence of definite space or time limits; quite the con- 

 trary. Every advance of knowledge only opens up new vistas into a 

 remoter past and discloses further depths of immensity teeming with 

 worlds." 



Thus the trnth urged against me is that we can not know any- 

 thing about these ultimate physical principles in their application 

 to the ultra-visible universe. But, unhappily for Professor Ward's 

 criticism, T entered this same caveat long ago. Demurring to that 

 doctrine of the dissipation of energy to which he now demurs, I 

 wrote : — 



" Here, indeed, we arrive at a barrier to our reasonings ; since we can 

 not know whether this condition is or is not fulfilled. If the ether which 

 fills the interspaces of our Sidereal system has a limit somewhere beyond 

 the outermost stars, then it is inferable that motion is not lost by radi- 

 ation beyond this limit ; and if so, the original degree of diffusion may 

 be resumed. Or supposing the ethereal medium to have no such limit, 

 yet, on the hypothesis of an unlimited space, containing, at certain inter- 

 vals. Sidereal Systems like our own, it may be that the quantity of molec- 

 ular motion radiated into the region occupied by our Sidereal System, 

 is equal to that which our Sidereal System radiates; in which case the 

 quantity of motion possessed by it, remaining undiminished, it may con- 

 tinue during unlimited time its alternate concentrations and diffusions. 

 But if, on the other hand, throughout boundless space filled with ether, 

 there exist no other Sidereal Systems subject to like changes, or if such 

 other Sidereal Systems exist at more than a certain average distance 

 from one another; then it seems an unavoidable conclusion that the quan- 

 tity of motion possessed, must diminish by radiation ; and that so, on 

 each successive resumption of the nebulous form, the matter of our 

 Sidereal System will occupy a less space; until it reaches either a state in 

 which its concentrations and diffusions are relatively small, or a state 

 of complete aggregation and rest. Since, however, we have no evidence 

 showing the existence or non-existence of Sidereal Systems throughout 

 remote space ; and since, even had we such evidence, a legitimate conclu- 

 sion could not be drawn from premises of which one element (unlimited 

 space) is inconceivable; we must be forever without answer to this tran- 

 scendent question." (First Principles, § 182, pp. 535-6.) 



See, then, how the case stands. After urging against me the 

 argument of " two eminent physicists " as fatal to my conclusions, 

 he thereupon expresses dissent from the premises of that argument; 

 and the reasons he gives for dissenting are like those given by me 

 before he was out of his teens! 



Tt is not always easy to disentangle misrepresentations; espe- 

 cially when they are woven into a fabric. For elucidation of this 

 matter there needs another section. It may fitly begin with an 

 analogy. An astronomer who "saw reason to think" that the 

 swarm of November meteors this year would be greater than usual, 

 would be surprised if the occurrence of a smaller number were 



