The Problem Stated 25 



horse before it can be found there, and it 

 requires work to do the putting. What work 

 associated with the different generations was 

 performed to produce this concentration of 

 energy? 



When energy exists in any body at the 

 same potential that it exists in similarly 

 situated bodies, there is nothing to excite 

 surprise or cause comment. The fact that 

 energy tends ever to equalize itself is a 

 sufficient explanation of uniform and equal 

 distribution. But when a body is found 

 which has energy at a higher potential than 

 that at which it exists in other bodies, some- 

 thing has occurred which demands explana- 

 tion. When it was discovered a few years 

 ago that radium maintained itself continu- 

 ously at a higher temperature than that of the 

 surrounding medium, Lord Kelvin remarked 

 that for the first time a question mark had 

 been placed opposite the doctrine of conserva- 

 tion of energy. That question mark, how- 

 ever, remained at that place a very short 

 time. The situation was so remarkable that 



