and the Modern World  (p. 141) the great discovery of the 
nineteenth century was the discovery of the method of 
discovery:

     The greatest invention of the nineteenth century was the 
     invention of the method of invention. A new method 
     entered into life. In order to understand our epoch, we can 
     neglect all the details of change, such as railways, 
     telegraphs, radios, spinning machines, synthetic dyes. We 
     must concentrate on the method in itself; that is the real 
     novelty which has broken up the foundations of the old 
     civilization. . . . One element in the new method is just the 
     discovery of how to set about bridging the gap between 
     the scientific ideas, and the ultimate product. It is a 
     process of disciplined attack upon one difficulty after 
     another.