374 HERMANN VON HELMHOLTZ 



philosophical and literary. The judgement of this one man is 

 accordingly of consummate value, and cannot be replaced by 

 any combination of judgements from individual professors, since 

 the questions brought before the Faculty are nearly always 

 those of the rival claims of the interests of the several depart- 

 ments ; and any one who combines all these, and deliberates on 

 them in his single mind, is the more capable of solving such 

 weighty and complicated problems correctly and completely/ 



Upon the pressing request of the Minister, that upon these 

 grounds, and from considerations referring to the salary, Helm- 

 holtz should remain in connexion with the University, he 

 declared his willingness to give a public lecture of two or three 

 hours in each term, ' provided he were relieved from the duty 

 of taking part in the executive work of the Faculty and the 

 Examinations/ 



On April 4, 1888, his appointment as President of the Physi- 

 kalisch-Technische Reichsanstalt was consummated. 



Despite the inevitable burden of organization Helmholtz felt 

 thoroughly happy and contented in his new post. He found 

 ample compensation for the many administrative duties (in which 

 he was assisted by a distinguished body of younger men) in the 

 stimulus of the innumerable problems that arose in the scientific 

 department of the Institute, and in the freedom from the 

 frequent repetition of experimental lectures and demonstrations, 

 which had absorbed so much of his time and energy. 



During the last year before he definitely took over the 

 Presidency of the Physico-technical Institute, Helmholtz had 

 been profoundly stirred by the work of Hertz, who sent 

 regular reports of his experiments to his former teacher. 



By the end of the year he was able to communicate his well- 

 known experiments on the interference between the effects 

 propagated along wires, and through the air, without at that 

 time being able to demonstrate a finite velocity of propagation 

 for these latter. Far greater surprises, however, were in store 

 for Helmholtz in Hertz's letters of the early months of the 

 ensuing year, 1888; his delight finds expression in the frequent 

 repetition of the words ' Bravo! Best congratulations' at the 

 end of his short answers : and when he sent to du Bois-Reymond, 

 for the Academy, the memoir in which Hertz proved that the 

 electrodynamic waves are reflected from solid conducting walls, 



