248 HERMANN VON HELMHOLTZ 



journey with you, but that is a trifle in comparison with the 

 long sad doom of half-existence. And every day convinces 

 me that the future will never improve either for him or for 

 us, although it is not much use talking about it.' 



Helmholtz was obliged to go off to the mountains to recruit 

 after the fatigues of Paris ; ' the fetes, &c. in the sultry heat were 

 so exhausting that I began again to have the fainting fits, from 

 which I had been free for some years/ On returning refreshed 

 to Heidelberg a few weeks later, he plunged once more into 

 his researches in mechanical acoustics, mathematical philosophy, 

 hydrodynamics, and electricity. On November 19, 1867, he 

 writes to Bonders : ' For the moment I am waiting for new 

 acoustic instruments, and am worrying over certain psychological 

 questions, the principles of space-perception, and the psychical 

 processes of sense-perception without words. I fancy one could 

 make a better analysis of this last chapter than the philosophers 

 have accomplished so far. . . . The French seem to be nibbling 

 now at my Sensations of Tone, and to more effect at any rate 

 than the German musicians.' 



During this winter Helmholtz and G. Wiedemann conceived 

 the notion of letting their wives undertake the translation of 

 Tyndall's lectures on Heat as a Mode of Motion. The 

 scientific portion of the book was to be carefully edited, and 

 there was to be a preface written and signed by both. Some 

 scruples of Wiedemann were set aside by Helmholtz in the 

 words : ' My wife thinks there would be no harm in letting our 

 friends know who did the translation; she thinks it would 

 be more objectionable if the world supposed that you and I had 

 wasted our time over such work/ 



This translation appeared in 1871 that of Tyndall's com- 

 memorative paper on ' Faraday as a Discoverer ' having been 

 published the year before with an interesting preface by 

 Helmholtz, in which he expressed his great veneration for 

 Faraday in magnificent language. We have already seen how 

 cordially Faraday welcomed Helmholtz on his repeated visits 

 to England : ' the absolute simplicity, modesty, and untroubled 

 purity of his disposition had a charm such as I have never 

 encountered in any other man/ But in Helmholtz's determina- 

 tion to translate Tyndall's lecture the personal element was 

 completely subordinated. He was not even swayed by his delight 



