TYNDALL AND HIS AMERICAN VISIT. 503 



establishment of fog signals on the coast of England. Indeed, his 

 studies branched out toward the practical in a variety of direc- 

 tions ; chief among them being his investigations concerning the 

 nature of the dust particles in the air, and their relation to the 

 germ theory of disease. 



It is said that he had from youth a faculty of examining his 

 premises with extreme minuteness, so that he was hardly ever 

 known to proceed on a false assumption ; and no theory ever pro- 

 pounded by him as the result of mature deliberation has been 

 upset or seriously controverted. Another of his characteristics 

 was that a research once entered upon, the work was carried on 

 with the unflagging industry and persistence of an enthusiast. 

 He has himself furnished the explanation of this in the following 

 passage taken from his later writings : 



My going to Germany had been opposed by some of my friends as quixotic, 

 and my life there might perhaps not be unfairly thus described. I did not work 

 for money ; I was not even spurred by the " last infirmity of noble minds." I bad 

 been reading Ficbte and Emerson and Carlyle, and had been infected by the spirit 

 of these great men. The Alpha and Omega of their teaching was loyalty to duty. 

 Higher knowledge and greater strength were within reach of the man who un- 

 flinchingly enacted his best insight. It was a noble doctrine. It held me to my 

 work, and in the long, cold mornings of the German winter, defended by a Schlaf- 

 rock lined with catskin, I usually felt a freshness and strength a joy in mere 

 living and working derived from perfect health which was something different 

 from the malady of self-righteousness. 



Again he says of this German experience : 



I risked this expenditure of time and money not because I had any definite 

 prospect of material profit in view, but because I thought the cultivation of the 

 intellect important because, moreover, I loved my work and entertained the sure 

 and certain hope that, armed with knowledge, one can successfully fight one's 

 way through the world. And I must not omit one additional motive, which 

 was a sense of duty. Every young man of high aims must, I think, have a spice 

 of this principle within him. There are sure to be hours in his life when his 

 outlook will be dark, his work difficult, and his intellectual future uncertain. 

 Over such periods, when the stimulus of success is absent, he must be carried by 

 his sense of duty. 



But it was his power as a scientific expositor that gave Prof. 

 Tyndall his worldwide reputation, and it is on this that his fame 

 chiefly rests. His ability to present even abstruse subjects to a 

 popular audience was unexcelled. The vividness of his imagina- 

 tion, which enabled him to form clear mental pictures of the phe- 

 nomena he sought to explain, and his aptness in illustration led 

 him to translate abstract ideas into their concrete equivalents. 



On this point, the Athenaeum remarks : 



His lectures were not merely marked by logical reasoning expressed in for- 

 cible language, but they were models of method: nothing was left to chance; 



