PROFESSOR AT HEIDELBERG 233 



were unable to do this properly ; we are going to see it more 

 thoroughly this afternoon. What I saw interested me greatly. 

 M. Cavallie, who has raised himself from a working man to be a 

 master-hand, is a most intelligent and original person. ... At the 

 concert at the Conservatoire we had a Symphony by Haydn, a 

 piece from Beethoven's Ballet of Prometheus, and the whole of 

 the music from the Midsummer Nights Dream, as well as 

 a chorus of Bach, and Handel's Hallelujah Chorus. One hears 

 better choral singing in Germany, but the perfection of the 

 orchestra is unique of its kind. The oboes in Haydn's 

 Symphony sounded like a gentle zephyr; everything was in 

 perfect tune, including the high opening chords of the Mendels- 

 sohn Overture, that are repeated at the end, and generally 

 sound out of tune. The Prometheus was the most enchanting 

 melody, with the horns predominating. This concert, after the 

 Venus of Milo, was the second thing of purest beauty that life 

 can give. ... I went with MM. Cavallie and Bussy to the house 

 of a harmonium-maker, Mustel, who wanted to show me his 

 latest invention, a tuning-fork piano, with sustained tones. This 

 confirmed my theoretical assumptions, and produced no special 

 effect, which fact, however, is of some importance for my theory. 

 The advance in the construction of the harmonium was very 

 striking ; it was like a very perfect and easily responding piano, 

 with every kind of contrivance in the mechanism, for bringing 

 out the treble parts. I used this opportunity to preach the un- 

 equal temperament for the organ, and M. Cavallie seemed in- 

 clined to make the experiment. . . . 



'On Wednesday I went first to M. Regnault's lecture at the 

 College de France. I was in hopes of seeing him experiment, 

 since he is one of our most famous experimenters, but he did 

 not ; he showed me his instruments, a collection renowned in 

 the history of physics. 



' I went to the cole Normale, where MM. Grandeau and 

 Deville had invited me, to visit the latter, and to see Herr 

 Konig's instruments. To my surprise M. Duruy, the Minister 

 of Instruction, also turned up with a member of his council, and 

 they begged me to give him a lecture on the analysis of the 

 vowel tones, which I did. . . .' 



Returned from Paris, Helmholtz at once went back to the 

 completion of his Physiological Optics, but was sorely disturbed 



