A MEMOIR OF GCTSTAV EOBERT KIRCHHOFF.* 



By Robert von Helmholtz. 



Translated by Joseph de Perott. 



On the 20th day of October of the past year (1887) we bade our last fare- 

 wells to Gustav R. Kirchboli" in St. Matthew's Cemetery at Berlin. Nat- 

 ural science has lost one of its mightiest promoters, Germany is bereft 

 of one of her keenest thinkers, the youth-lament their honored, brilliant 

 master, and his friends mourn over a man who belonged to the best, in 

 the true meaning of this word. While Kirchhoff 's works made his name 

 immortal, so that wherever physics is taught he will be mentioned, such 

 were his modesty and simplicity that his own person was hidden behind 

 the object to which he devoted his life, and if we except his colleagues 

 and those who had the fortune to be near him, there were very few 

 who knew more than that Kirchhoff was the illustrious discoverer of 

 spectrum analysis. Let one of his students be permitted to attempt to 

 do what he would never have undertaken himself and what even would 

 have been painful to him while he lived, — to draw a picture of his work 

 not in its ])ure, abstract form, destitute of all earthly vesture, as he pro- 

 duced it, but rather in connection with his personal life, and as a fruit 

 of his personal genius. 



Gustav R. Kirchhoff" was a professor of mathematical physics. I mention 

 this first, not because it is the main fact which would stand first in a 

 biographical dictionary, but because mathematical physics is a science 

 of which only he who was born to it can become an adept.. There are 

 vocations in life, there are branches of science that do not allow us to 

 infer what spirit animates their adepts. In certain regions of abstract 

 science however, whoever wants to penetrate into them, must have fac- 

 ulties and dispositions of definite nature and bias, otherwise he will not 

 even cross the threshold that leads to them. 



Pure mathematics is such a science. Everyday experience teaches us 

 that only a small proportion of students are endowed with a genius for 

 it. It is more difficult to say on tvhat powers of the human mind such 

 a genius rests. Mathematics is logic applied to numbers and extensiv^e 

 magnitudes. It requires accordingly a great power of abstraction and 

 the faculty of intuitive percei)tion of relations of magnitudes. At any 



*Froin the Deutsche Rundschau, February, 1888 : vol. xiv, pp. 232-245. 



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