194 



SCIENCE. 



[N. S. Vol. III. No. 58. 



Perhaps Nature has shown herself most 

 reticent and unyielding when scientific men 

 have questioned her as to the ultimate 

 structure of matter, the full knowledge of 

 which includes a satisfactory explanation 

 of the force of gravity which is one of its 

 essential properties. Hypotheses which 

 have been very useful in their time have 

 been finally rejected because they involved 

 some impossible conception, such as action 

 at a distance, which was for a long time 

 believed possible. The tendency is now 

 and has long been to regard space, or at 

 least that part of it in which we have any 

 particular interest, as a plenum and to as- 

 sume a continuous, incompressible, friction- 

 less elastic fluid in which and of which all 

 things are. In the development of his ex- 

 quisite theory of vortex motion, Helmholtz 

 demonstrated the possibility of a portion of 

 such a fluid being differentiated from the 

 rest in virtue of a peculiar motion impressed 

 upon it, and that when so differentiated it 

 must forever remain so, a fact which was 

 quickly seized upon by Lord Kelvin as the 

 foundation of a vortex theory of matter, 

 thus sharing with Helmholtz the honor of 

 having approached nearer than all others 

 to the solution of the great mystery. 



From the genesis of an atom to the origin 

 of the universe seems a long step, but it is 

 not too great for the intellect of man. The 

 well-known Nebular Hypothesis was ad- 

 vanced long before Helmholtz's time, but a 

 better knowledge of Thermodynamics had 

 quite upset one of its generally accepted 

 principles, namely, that the original nebu- 

 lous matter was fiery hot. As long ago as 

 1854 Helmholtz showed that this was not 

 a necessary assumption and proved that 

 mutual gravitation between the parts of the 

 sun might have generated the heat to which 

 its present high temperature is due. The 

 greatest philosophers of the past hundred 

 years have attempted to account for this 

 high temperature and for its maintenance, 



on which all life on this globe depends. 

 The simple dynamical theory of Helmholtz 

 has survived all others and is to-day uni- 

 versally accepted. 



But I must cut short this absolutely inade- 

 quate account of what the scholar did, that 

 I may say a word or two of what the man 

 was. Although one of the most modest and 

 quiet of men, no one could meet him with- 

 out feeling the charm of his personality. 

 Although he bore a dignity which became 

 the great master of science which he was 

 everywhere admitted to be, he was approach- 

 able in an extraordinary degree. He was 

 eloquent in popular address and believed in 

 the obligations of men of science to the gen- 

 eral public. In scientific discussion, whether 

 on his feet or with pen in hand, there 

 was a certain massiveness about his style 

 and manner which was generally irresist- 

 ible. In his attacks upon the region of the 

 unknown he showed possibly less brilliant 

 strategy than one or two of his contem- 

 poraries, but he rarely, if ever, found him- 

 self obliged to conduct a retreat. In 1893 

 he was selected by the Emperor as the head 

 of the German delegation, five in number, 

 to the International Electrical Congress 

 held in Chicago in August of that year. 

 His more than three score and ten years 

 weighed upon him, and he begged to be re- 

 lieved of the duty. The young Kaiser, who 

 was fond of him and who loved to honor 

 him in every way, sent for him. On hear- 

 ing his modest plea he said, " Helmholtz, 

 you must go ; I want the Americans to see 

 the best I have of every kind, and you are 

 our greatest and best man." As becomes a 

 dutiful subject he yielded. While in this 

 countrj^ every honor was shown him. Here 

 he found many of the hundreds or thousands 

 of his pupils who everywhere in the world 

 are adding lustre to his name by perpetu- 

 ating his spirit and his methods, and all 

 were ready to serve him. Electrician, 

 mathematician, physiologist and physicist, 



