Problem of Partition of Energy. 665 



possibly altered in the process. Thus — in analogy with the 

 passage of heat energy in diminished (or increased) amount 

 from a region o£ high to one of low temperature (or con- 

 versely), in association with the necessary performance for 

 absorption) o£ external work — we have the transformation 

 of radiation from one wave-length to another in association 

 with the performance or absorption of work. The disturbance 

 has equal opportunities for the occupation of each cell. These 

 postulates lead to Planck's law, the constants only having 

 important modifications of meaning. 



3. Jeans has recently discussed Larmor's view, and arrives 

 at the conclusion (Ph;l. Mag. Dec. 1910) that it is neither 

 possible to avoid finiteness of the element of energy nor 

 ultimate discontinuity of aether structure in relation to 

 radiation if Planck's law corresponds to the true final con- 

 dition of equilibrium. That is to say, radiation can only be 

 regarded as capable of existing in the aether in amounts 

 which are multiples of a finite unit. 



While J( ans's own view (§ 1) must be recognized as indi- 

 cating a possible solution of the fundamental difficulty 

 regarding the partition of energy, it is not possible, because 

 of our ignorance of the intrinsic nature of matter, of 

 aether, and of the connexion between these, to be quite 

 certain that Larmor's view, or even Planck's, is inadmissible. 

 It is perhaps not impossible that the nature of these entities 

 may impose identity between the distribution which obtains 

 in the steady state under experimental conditions and that 

 which w r ould obtain in the final state of a strictly conser- 

 vative self-contained system. I therefore venture to indicate 

 the following mode of considering the problem. It leads to 

 an expression which differs slightly in form from that of 

 Planck, but which can practically be identified with it 

 throughout* tire range of observed wave-lengths, and which, 

 with it, reduces to fiayleigh's form when the wave-length is 

 of suitable magnitude. 



4. Interchange of energy amongst freedoms of the same- 

 type .constitutes .ordinary transmission of energy of the type 

 involved ; interchange of energy amongst freedoms of distinct 

 types constitutes that transmission of energy which is ordi- 

 narily called transformation. When different sub-systems, 

 in the equilibrium condition, are freely open to interchanges 

 of energy, a universal generalized temperature or potential, 

 possessing a definite statistical value throughout the total 

 system when that system possesses a definite total amount of 

 energy, must exist. 



