THE ORIGIN OF COSMICAL EN 7 ERGY 33 



whether in peace or war, for a modicum of the means 

 of existence, science tells us that, in the commonest 

 materials that make up the framework of the world, 

 there is energy of a magnitude of which we have no 

 experience, and the means of livelihood upon a scale of 

 which we have no standard. The energy is there. 

 The knowledge that can utilise it is not not yet. 



If the nineteenth century is destined to be 

 remembered in history on account of the establish- 

 ment of the doctrine of energy, to the twentieth, 

 young as it still is, belongs the credit of elevating and 

 extending that doctrine to the extent that makes it 

 of universal human interest. One simple question 

 concerning the source of energy the nineteenth 

 century quite failed to answer. Divorcing from the 

 problem everything but its purely physical aspect, 

 and putting it in its widest form, there remained 

 unanswered the problem of its origin. How is it 

 that the world is not yet grown old and "dead," 

 though geologists dispute among themselves whether 

 its history, in much the same condition as at present, 

 can be traced back a hundred million or a thousand 

 million years? Or, look up on a clear night at the 

 same stars as those that greeted the gaze of the cave- 

 dweller and the mastodon when man was young. 

 How can nature, the bank-teller, account for such 

 a large expenditure of energy, over so prolonged 

 a period, without long ago having become bankrupt ? 

 The sun and stars do not burn coal. Even if they 

 did, Lord Kelvin computed that the combustion of 

 a mass of coal the size of the sun would only suffice 

 for 5000 years of the present rate of output of 

 solar energy. Though, without any new source of 

 energy, it was found by him to be possible to account 

 for solar radiation over a period of some millions of 

 years, the claims of the geologists for hundreds or 

 thousands of millions could not be satisfied. What 



