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XL. A Question regarding one of the Physical Premises upon 

 which the Finality of Universal Change is based. By S. 

 Tolver Preston*. 



I" SHOULD like to add a few remarks by way of appendix 

 to my paper on the subject of recurring changes in the 

 universe '(' Nature,' March 20, 1879, and Philosophical Maga- 

 zine, August, 1879). All I wish to deal with is one point 

 regarding the physical premises upon which the view of 

 finality in the universe is based ; and the fact of having pro- 

 posed a theory of the aether f (a body which affects this 

 question in the most intimate manner) may perhaps warrant 

 my saying a few words. It is of course not my intention 

 here to question in any way the conclusion of the tendency to 

 the establishment of a general equilibrium of temperature in 

 the universe. My object is rather to suggest a reconciliation 

 of this with a means for recurring change. 



The view of those who believe that physical evidence points 

 to ultimate finality and cessation of life in the universe, 

 could not perhaps well be summarized with greater clearness 

 than in the following passage from Prof. Balfour Stewart's 

 work ' The Conservation of Energy ' (3rd edition, 1874) under 

 heading " Probable Fate of the Universe," viz. :- u We have 

 spoken already about a medium pervading space, the office of 

 which appears to be to degrade and ultimately extinguish all 

 differential motion, just as it tends to reduce and ultimately 

 equalize all difference of temperature. Thus the universe 

 would ultimately become an equally heated mass, utterly 

 worthless as far as the production of work is concerned, since 

 such production depends upon difference of temperature. 

 Although, therefore, in a strictly mechanical sense there is a 

 conservation of energy; yet, as regards usefulness or fitness 

 for living beings, the energy of the universe is in process of 

 deterioration. Universally diffused heat forms what we may 

 call the great waste-heap of the universe, and this is growing 

 larger year by year. At present it does not sensibly obtrude 

 itself; but who knows that the time may not arrive when we 

 shall be practically conscious of its growing bigness. It will 

 be seen that in this chapter we have regarded the universe, 

 not as a collection of matter, but rather as an energetic agent — 

 in fact, as a lamp. Now, it has been well pointed out by 

 Thomson that, looked at in this light, the universe is a system 

 that had a beginning and must have an end ; for a process 



* Communicated by the Author. 



tPhil. Mag. Sept. & Nov. 1877, Feb. 1878; 'Nature,' Jan. 15th, 

 1880, &c. 



