32 PHYSICAL RESEARCH 



phenomenon was new, and he quickly investigated 

 its main properties; the fact that the bones cast 

 a deeper shadow than the flesh was soon noted, 

 and the application to surgery was obvious. This 

 was the actual march of events. How could it 

 have been reversed? But even if human thought 

 had been able to frame the request in the period 

 before the fundamental experiment, there would 

 still have been an irreversible process in the way. 

 The question put, who could have answered it ? 

 Imagine a committee of the greatest scientists of 

 the time meeting to devise experiments for the 

 purpose. It is safe to say that they would not have 

 had any idea of the direction in which they should 

 move, and that with all their knowledge and all 

 the resources of the science of the day at their 

 disposal they would have been helpless. They 

 could not have anticipated the discovery which 

 was to be made shortly afterwards, almost without 

 effort, as a natural development of a well-known 

 line of research. 



Lastly, the final experiment of Rontgen's would 

 never have been made except as a natural sequence 

 to a long series of researches which preceded it. 

 Consider for a moment the stock of initiative, of 

 ideas and of apparatus which were available to 

 Rontgen at the time. Why should he have been 

 examining the electric discharge at all? It was 

 because it had long been instinctively felt that in 

 the examination of the electric discharge lay a 



