3 8 HERMANN VON HELMHOLTZ 



On July 21 he announced to du Bois-Reymond that he would 

 bring forward his ' Conservation of Energy ' on the 23rd at the 

 Physical Society. The meeting was one of the most memorable 

 in the annals of the Society ; as du Bois tells us, Helmholtz 

 revealed himself at one bound, to the surprise of all his friends, 

 as a master of mathematical physics. The members of the 

 Physical Society were acquainted with the Law of the Con- 

 servation of Energy when it was still unknown to all the rest 

 of the world. 



As soon as the meeting was over Helmholtz sent the manu- 

 script to Magnus, with whom he was on very friendly terms, 

 begging him to arrange for its publication in Poggendorff J s 

 Annalen. But Magnus, though he willingly and cordially 

 recognized the merits of Helmholtz's essay, took exception to 

 the character of his work. He regarded experimental and 

 mathematical physics as separate departments, and warned him 

 repeatedly against undue partiality for mathematics, and the 

 attempt to bring remote provinces of physics together by 

 its means. Accordingly he only sent the memoir with 

 a few words of general recommendation to Poggendorff, and 

 this apparently not till he was constrained to it by du Bois- 

 Reymond, who, with Brucke, had all the younger physicists 

 and physiologists of the Physical Society upon his side. 

 Poggendorff replied that the subject-matter was not in his 

 opinion sufficiently experimental to justify him in publishing it 

 in the Annalen, though he acknowledged its importance as 

 a theoretical treatise. Both he and Magnus therefore advised 

 the author to bring it out as an independent publication. Du 

 Bois forwarded these letters to Helmholtz with forcible ex- 

 pressions of his annoyance with Poggendorff and Magnus, 

 urging him if possible to get the essay published by Reimer 

 in Berlin as a pamphlet, and recommending him to restore 

 the Philosophical Introduction. Helmholtz did not allow 

 his satisfaction in the work to be destroyed by the reser- 

 vations of the older physicists, but he altered certain 

 parts of the Introduction in order still further to emphasize 

 his position in regard to the prevailing scientific concep- 

 tions. This Introduction was the foreword of modern 

 science in the second half of the nineteenth century, while 

 its fine and simple style already proclaim its author a 



