2 o8 HERMANN VON HELMHOLTZ 



years' time were to reveal the depth of his mathematical and 

 philosophical conceptions to the scientific world. During the 

 next ten years, Helmholtz displayed an illumination in his 

 view of scientific problems, an elevation of philosophical 

 conception, a purposeful attitude in regard to the riddles and 

 mysteries of Nature, a grasp of all the resources of thought 

 and feeling available for the investigation of the whole field of 

 human knowledge, such as are seldom met with in the history 

 of the sciences, and can only be appreciated in their full extent 

 and significance by those who had the privilege of personal 

 contact with this extraordinary genius. 



In his youth his friends du Bois-Reymond, Brttcke and 

 Ludwig had applauded his marvellous discoveries, and now it 

 was Bunsen and KirchhofT who were amazed at his scientific 

 achievements. Long after KirchhofT had won immortal fame 

 by his discovery of spectrum analysis, he used to say, modestly 

 indeed, but none the less truly, ' I am content if I can even 

 understand a single work of Helmholtz, but there are still 

 many points in his great book on acoustics that I cannot unravel/ 



It was to this time of intellectual activity that Helmholtz 

 referred when he said thirty years later in his celebrated speech 

 on the commemoration of his 7oth birthday, November 2, 1891 : 



'There are many narrow-minded people who admire them- 

 selves enormously if they have one stroke of luck, or think 

 that they have had one. A pioneer in science, or an artist, 

 who has a repeated run of happy accidents, is indubitably 

 a privileged character, and is recognized as a benefactor of 

 mankind. But who can count or weigh such lightning flashes 

 of the mind ? Who can trace out the secret threads by which 

 our conceptions are united ? For 



Was vom Menschen nicht gewusst, 

 Oder nicht bedacht, 

 Durch das Labyrinth der Brust 

 Wandelt in der Nacht. 



' I must confess that the departments in which one has not to 

 trust to lucky accidents and inspirations have always had the 

 greatest attraction for me. Yet as I have often been in the 

 predicament of having to wait on inspiration, I have had some 

 few experiences as to when or how it came to me, which may 

 perhaps be of use to others. Often enough it steals quietly 



