PROFESSOR AT HEIDELBERG 221 



' I have had to serve the Public and Mammon, and to treat the 

 Conservation of Energy as the milch cow. I have given eight 

 lectures on it in Karlsruhe, and am preparing to do the same 

 in London at Easter in English. I always look on a journey 

 to England as a kind of intellectual " cure ", which shakes one 

 out of the comfortable indolence of dear old Germany into 

 more active life, and lectures such as I gave there once before 

 are a good means of establishing closer working relations with 

 the English men of science.' 



In 1863 the families of Helmholtz and Kirchhoff moved into 

 the new ' Friedrichsbau ', which for those days was a fine and 

 roomy group of buildings, containing laboratories, lecture-rooms, 

 and dwellings for the staff. Helmholtz's house was always the 

 centre of a delightful society, where plain living and high 

 thinking were the order of the day. He had formed close 

 friendships with his colleagues, Kirchhoff, Bunsen, and Zeller, 

 while the Helmholtz family was in intimate social relations 

 with those of von Vangerow, Haeusser, Gervinus, Friedreich, 

 Kopp, Wattenbach, and others. Under these improved con- 

 ditions he was able to attend more to his children, and personally 

 superintended the education of his son Richard, who had entered 

 the Heidelberg Gymnasium in 1862. 



The latter writes : ' With regard to the intercourse between 

 my father and his children, it was chiefly at meals and out 

 walking that we saw him. In bad weather we went by the 

 Rohrbacher Landstrasse, otherwise generally to the Wolf's 

 Hohle, Gaisberg, Sprung, Philosophenweg, &c. It gave him 

 keen pleasure to show us any natural phenomenon ; I shall 

 never forget one autumn morning of thick fog, when he saw 

 there would be sunshine up above, and took us by the Sprung- 

 weg, to show us the rolling, sharply defined sea of mist, with 

 only a few spires rising out of it. In the winter of 1862 my 

 father taught me to draw with mathematical instruments, and 

 in 1863 essayed to teach us the elements of thorough-bass, 

 which succeeded very well with my sister at any rate/ 



In the Easter holidays Helmholtz spent some weeks in 

 England, staying on the way in Utrecht with his friend 

 Bonders, whom he found 'as blooming, affectionate, and 

 poetical as ever', and in whose house he passed several very 

 pleasant days. 



