Nipher — Physics During the Last Century. Ill 



beyond our reach. The water which has turned the mill, may 

 be again lifted to the hills, and may return to drive the same 

 mill again, but the energy which thus apparently reappears, 

 has not really done so. It is a new supply of energy fur- 

 nished us in solar radiation. And this source of energy thus 

 tremendously drawn upon will finally fail. 



In 1854 Helmholtz computed the total heat resulting from 

 the condensation of the sun and planets, from an initial con- 

 dition of zero density, to their present condition. He con 

 eluded that only about the 454th part of the original energy 

 remains as such, and that the heat which has already been dissi- 

 pated into space, would raise the temperature of a mass of 

 water equal to that of the sun and planets, to a temperature 

 of 28 million degrees centigrade. He pointed out that all of 

 the operations of our universe are of a descending character. 

 It is a great clock which is running down. Carried backward 

 in time these newly discovered laws point to a beginning of 

 the present order of things. All the energies expended 

 through historic time, whether those of Nature, or those 

 which man has drawn upon, used and wasted, were potentially 

 present in a cold and lifeless nebula. The struggles of men 

 to enslave their fellows, and the struggles of men to be free, 

 the energy which drives the pen, the cannon-shot and the 

 mill, were all expressions of portions of the initial energy of 

 this infinitely diffused gaseous mass, which we now in its 

 present condition call the solar system. 



And if we would know of the future, these same laws tell 

 us that the history of our universe will end as it began, in 

 cold and stillness and universal night. The matter in the 

 solar system, instead of being infinitely diffused, will have 

 gravitated into a solid mass. The energy which it once con- 

 tained will have been radiated into the ether, which fills all 

 space around. The energy of the matter of the universe, 

 will have been transferred to the ether. Are these ether 

 wavelets crossing and interlacing forever in reflection from 

 some envelope which bounds our universe, and separates it 

 from a fathomless, unknown beyond? or do they continue 

 outward forever into a space which is absolutely without 

 limit? Is our infinite the first of an infinite series of infinite 



