PROFESSOR AT HEIDELBERG 249 



in describing how Faraday had with a mysterious instinct made 

 the most pregnant discoveries in natural science, although he was 

 unable subsequently to give any clear account of the train of 

 ideas that led to them : Faraday's development rather appeared 

 to him of the greatest general human interest for many 

 theoretical questions in psychology, and for a number of practical 

 problems in education, and he regarded it as a most interesting 

 phenomenon that the man who had remained true to the pious 

 faith of the small sect of his forebears, should have developed a 

 philosophic vein, 'in virtue of which he ranks among the foremost 

 in the general scientific thought of the age/ In characteristic 

 language, Helmholtz (without direct allusion) sums up the total 

 of the great researches which he himself had so ably shared in 

 and initiated during the past thirty years of his life. 



1 After our era had destroyed the old metaphysical idols in 

 its legitimate effort to render human knowledge above all the 

 true image of reality, it was arrested by the traditional forms 

 of the physical concepts of matter force, atoms, impondera- 

 bilities and these names became to some extent the new 

 metaphysical catch-words of the very people who had seemed 

 the most enlightened. It was these concepts that Faraday 

 sought again and again, in his maturer work, to purify from 

 whatever they still contained that was theoretical, and not the 

 immediate and just expression of the facts.' 



In the same year he also published the first volume of the 

 German translation which he and Wertheim had made of 

 Thomson and Tait's Textbook of Theoretical Physics, with a 

 short preface by Helmholtz, in which he expresses the gratitude 

 of the scientific world to William Thomson (Lord Kelvin), one 

 of the most inventive and penetrating of thinkers, for admitting us 

 to the laboratory of his thoughts, and unravelling for us the clues 

 which had aided him in controlling and ordering the confused 

 and refractory material with which he had to deal. He points 

 out that in this work physical consistency was preferred to 

 elegance of mathematical method. ' Perhaps when science is 

 perfected, physical and mathematical order may coincide/ 



The second part of Vol. I of Thomson's Theoretical Physics 

 only appeared in 1874 (when Helmholtz and Wiedemann also 

 published their translation of Tyndall's Lectures on Sound), with 

 an introduction written at the end of 1875, entitled ' Critical '. 



