PRIMARY CONCEPTS OF MODERN SCIENCE. 705 



tiquated position, Prof. Agassiz is never likely to show. This is 

 largely because Lyell has always been a thinker of purely scientific 

 habit, while Agassiz has long been accustomed to making profoundly 

 dark metaphysical phrases do the work which properly belongs to 

 observation and deduction. But, however we may best account for 

 these idiosyncrasies, it remains most probable among those facts which 

 are still future, that Prof. Agassiz will never advance any more crush- 

 ing refutation of the Darwinian theory than the simple expression of 

 his personal dislike for " mechanical agencies," and his belief in the 

 " free manifestations of an intelligent mind." Were he only to be left 

 to himself, such expressions of personal preference could not mar the 

 pleasure with which we often read his exposition of purely scientific 

 truths. But when he is brought before the public as the destroyer of 

 a theory, the elements of which he has never yet given any sign of 

 having mastered, he is placed in a false position, which would be lu- 

 dicrous could he be supposed to have sought it, and which is, at all 

 events, unworthy of his eminent fame. 



-- 



THE PEIMAEY CONCEPTS OF MODEEN PHYSICAL 



SCIENCE. 



ERRATUM. 



Page 710, line 32, for "impenetrability," read " compenetrability." 



"Natural science," says Du Bois-Eeymond, 1 "is a reduction of the 

 changes in the material world to motions of atoms caused by central 

 forces independent of time, or a resolution of the phenomena of Na- 

 ture into atomic mechanics. . . . The resolution of all changes in the 

 material world into motions of atoms caused by their constant central 

 forces would be the completion of natural science." 



Obviously, the proposition thus enounced assigns to physical sci- 



1 " Ueber die Grenzen des Naturerkennens. Ein Vortrag in der zweiten offentlichen 

 Sitzung der 45. Versammlung deutscher Naturforscher und Aerzte zu Leipzig am 14. 

 August 1872, gehalten von Ernil Du Bois-Reymond." Leipzig, Veit & Comp., 1872. 

 VOL. III. 45 



