1 have in the foregoing reminiscences frequently 

 had occasion to make some explanatory observations on 

 my technical papers, which are described in the second 

 volume of the collection of my ' 'Scientific and technical 

 papers" published in the years 1889 and 1891 by 

 Julius Springer*). I have called attention to most of 

 my earliest scientific writings, as they have had great 

 influence on my career, and as they have probably 

 remained unknown to the younger generation of physi- 

 cists. I feel however the need of making also some 

 critical remarks, accompanied by an estimate of results, 

 on my later scientific work, which in many points 

 diverges from the accustomed paths of the prevalent 

 physical theories and has therefore found no general 



recognition. 



In several papers written in the years 1860 to 

 1866, and published in Poggendorff 's Annalen, I in- 

 vestigated the question of the electric conductivity of 

 metals, and proposed the first and up till now only 

 method of obtaining an empirical reproducible standard 

 of resistance. I showed that my method made it 

 possible to determine exactly the resistance of an 



*) English edition published by John Murray. 



