718 HERMANN A^ON HELMHOLTZ. 



year. The preface was sigued by Vou Helnilioltz, and thus the career 

 of the great investigator was fittingly ckjsed by the inauguration of a 

 national college devoted to learning and research. 



In a brief and imperfect sketch such as this it is barely possible to 

 give an idea of the extent of the work of Von Helmholtz; it is certainly 

 impossible to do justice to its fulness and depth. I have mapped the 

 directions of the main streams of his thought. Only those who follow 

 them in detail can count the fields they have fertilized. In the course 

 of his investigations all sorts of side issues were studied, a vast number 

 of subsidiary problems solved. The alertness of his intellect, the read- 

 iness with which he turned from one science to another, the extraor- 

 dinary ease with which he handled weapons the most diverse and the 

 most difficult to master, these are not less wonderful than the catalogue 

 of his main achievements. 



The technical merits of his work will, of course, be appreciated 

 chiefly by experts. Special knowledge is not necessary to understand 

 its importance. He was one of the first to grasp the xjrinciple of the 

 conservation of energy. He struck, independently and at a critical 

 moment, a powerful blow in its defense. He penetrated further than 

 any before him into the mystery of the mechanism which connects us 

 with external nature through the eye and the ear. He discovered the 

 fundamental properties of vortex motion m a perfect liquid, which have 

 since not only been applied in the explanation of all sorts of physical 

 phenomena, of ripple marks in the sand and of cirrus clouds in the air, 

 but have been the bases of some of the most advanced and pregnant 

 speculations as to the constitution of matter and of the luminiferous 

 ether itself. 



These scientific achievements are not, perhaps, of the type Avhich 

 most easily commands general attention. They have not been utilized 

 in theological warfare; they have not revolutionized the daily business 

 of the world. It will, however, be universally admitted that such tests 

 do not supply a real measure of the greatness of a student of nature. 

 That must finally be appraised by his j)ower of detecting beneath the 

 complication of things as they seem something of the order Avhich 

 rules things as they are. Judged by this standard, few names will 

 take a higher i)lace than that of Hermann vou Helmholtz. 



