232 HERMANN VON HELMHOLTZ 



obliged him to go to Engelberg for three weeks in the autumn, 

 to drink whey. After a sharp walking tour through the Mont 

 Blanc district the attacks became less frequent and less severe, 

 but when he resumed his work, and more especially during 

 the epistemological portions of it, his health once more suffered 

 severely ; ' the attacks still make all occupation impossible, 

 each onset robs me of twenty-four hours* work.' 



His condition obliged him to take a fortnight's rest again 

 during the Easter holidays, and he went to Paris, where he 

 found a hospitable and affectionate welcome from his wife's 

 uncle Julius von Mohl, the famous Orientalist. A short break 

 in the journey was devoted to Strassburg, where he ascended 

 the gallery of the Cathedral Tower, and gloried in the bold 

 stonework. ( I looked into old Ulrich's riddle about the square 

 and the octagon; the solution is very simple.' He spent the 

 first evening in Mohl's house, ' peacefully, and I hope with 

 mutual satisfaction.' He sent full and interesting accounts of his 

 daily doings by letter to his wife, who was familiar with Paris and 

 all its striking personalities from her long stay with her aunt. 



4 ... At eleven o'clock I had to be back for a breakfast with 

 M. Hermite and the mathematician Prof. Smith from Oxford. 

 It was said in course of conversation that there had been some 

 notion of inviting me to go to Oxford as Professor of Physics. 

 However, they could not offer more than 700 salary, which of 

 course is more than we get in Heidelberg, but hardly enough to 

 live comfortably in England. ... So I think Prof. Max M uller 

 was right to say he could tell them decidedly that I should not 

 accept it. ... M. Hermite was very complimentary to me, and 

 introduced me to a^M. Grandeau, who came to welcome me, and 

 escort me to the Ecole Normale, where the chemist, St. Claire 

 Deville, a rising man of the first rank, received me very warmly. 

 He took me into the Physical Department, where we had to 

 pass through a class-room in which a lesson was being given in 

 physics. I was presented to the scholars, and received with 

 rounds of applause, since they are all, at least so I was told, well 

 acquainted with my acoustical theories. . . . 



' Grandeau and Laugel took me to the first of organ-builders, 

 Cavallie-Col, who showed us his workshop, and then accom- 

 panied us to the Church of St. Sulpice, to inspect the largest 

 organ in Europe, built by him, but on account of the service we 



