AUTHOR'S PREFACE 



I DECIDED at the end of last year, in consequence 

 of my long personal and scientific connexion with 

 Hermann von Helmholtz, and at the repeated wish 

 of his widow, the late Frau Anna von Helmholtz, to 

 compile a Biography of the great investigator. 



Thanks to the letters and other communications 

 received from his family and from a vast number of 

 distinguished scholars and friends, to the permission 

 accorded by the Prussian Government to avail myself 

 of the Official Papers relating to the career of Helm- 

 holtz, and above all to the active co-operation of his 

 daughter, Frau Ellen von Siemens, I have been 

 enabled to give a connected account of his life; for 

 this help I beg to express my cordial thanks. 



It is for the indulgent reader to decide whether it 

 lies within the power of a mathematician to present 

 the epoch-making contributions of von Helmholtz to 

 the most various departments of human knowledge 

 in a form that shall be universally intelligible. 



LEO KOENIGSBERGER. 

 HEIDELBERG, 



October, 1902. 



In the English edition the Life has been slightly abridged, with 

 the permission of the author and German publishers. 



