HERMANN VON HELMHOLTZ 



establishment of a unit of light ; the testing of tuning 

 forks, the construction of universal screws, and, in- 

 deed, all methods and instruments having to do with 

 higher technical research and instruction. The In- 

 stitution had at least one point of contact with the 

 medical profession, as we find that 25,000 clinical 

 thermometers were tested and stamped during the 

 first three years. 



Werner von Siemens, whose admiration for the 

 talents of his friend was boundless, wished Helmholtz 

 to be entirely relieved from teaching, so as to leave 

 his energies freedom to work in the higher regions of 

 research, but circumstances made it important that 

 Helmholtz should retain his chair. This he did till the 

 year of his death in 1894, lecturing during the session 

 twice a week on such special subjects as the mathe- 

 matical theory of vibrations, electrodynamics, and the 

 mathematical developments of light and sound. In 

 the Institute, with a staff of fifty officials, Helmholtz 

 had now to undertake much administrative work, and 

 he performed this part of his duties with the same 

 zeal and thoroughness that had characterised his whole 

 life. It was certainly work different from that to 

 which he had been accustomed, far removed, for 

 example, from the fascinating study of sense-percep- 

 tions, but it was public work to which Helmholtz 

 attached great importance. His mind still soared into 

 the loftiest regions of scientific thought, and some of 

 his most advanced papers on mathematical physics 

 186 



