NA JURE 



389 



THURSDAY, MARCH 8, 1877 



SCIENTIFIC WORTHIES 

 X.— Hermann Ludwig Ferdinand Helmholtz 



rHE contributions made by Helmholtz to mathema- 

 tics, physics, physiology, psychology, and aesthetics, 

 are well known to all cultivators of these various subjects. 

 Most of those who have risen to eminence in any one of 

 these sciences have done so by devoting their whole atten- 

 tion to that science exclusively, so that it is only rarely that 

 the cultivators of different branches can be of service to 

 each other by contributing to one science the skill they 

 have acquired by the study of another. 



Hence the ordinary growth of human knowledge is by 

 accumulation round a number of distinct centres. The 

 time, however, must sooner or later arrive when two or 

 more departments of knowledge can no longer remain 

 independent of each other, but must be fused into a con- 

 sistent whole. But though men of science may be pro- 

 foundly convinced of the necessity of such a fusion, the 

 operation itself is a most arduous one. For though the 

 phenomena of nature are all consistent with each other, 

 we have to deal not only with these, but with the hypo- 

 theses which have been invented to systematise them ; 

 and it by no means follows that because one set of obser- 

 vers have laboured with all sincerity to reduce to order 

 one group of phenomena, the hypotheses which they have 

 formed will be consistent with those by which a second 

 set of observers have explained a different set of pheno- 

 nomena. Each science may appear tolerably consistent 

 within itself, but before they can be combined into one, each 

 must be stripped of the daubing of un tempered mortar by 

 which its parts have been prematurely made to cohere. 



Hence the operation of fusing two sciences into one 

 generally involves much criticism of established methods, 

 and the explosion of many pieces of fancied knowledge 

 which may have been long held in scientific reputation. 



Most of those physical sciences which deal with things 

 without life have either undergone this fusion or are in a 

 fair state of preparation for it, and the form which each 

 finally assumes is that of a branch of dynamics. 



Many cultivators of the biological sciences have been 

 impressed with the conviction that for an adequate study 

 of their subject a thorough knowledge of dynamical 

 science is essential. But the manner in which some of 

 them have cut and pared at the facts in order to bring the 

 phenomena within the range of their dynamics, has tended 

 to throw discredit on all attempts to apply dynamical 

 methods to biology. 



We purpose to make a few remarks on a portion of the 

 scientific work of Helmholtz, who is himself the most 

 illustrious example not merely of extensive acquaintance 

 with science combined with thoroughness, but of a tho- 

 roughness which of itself demands the mastery of many 

 sciences, and in so doing makes its mark on each. 



Hermann Ludwig Ferdinand Helmholtz was born 

 August 31, 1 82 1, at Potsdam, where his father, Ferdi- 

 nand Helmholtz, was Professor of the Gymnasium. His 

 mother, Caroline Penn, was of an emigrated English 

 family. His father's means would not admit of his study- 

 ing science otherwise than as a medical student. He 

 Vol. XV.— No. 384 



therefore became a military surgeon, and continued in 

 that position till the end of 1848, when he was appointed 

 Assistant of the Anatomical Museum of Berlin, and 

 Teacher of Anatomy at the Academy of Arts. In the 

 following year he went to Konigsberg, in Prussia, as Pro- 

 fessor of Physiology. In 1856 he became Professor of 

 Anatomy and Physiology at the University of Bonn ; in 

 1859, Professor of Physiology at the University of Heidel- 

 berg ; and, in 1871, Professor of Natural Philosophy to 

 the University of Berlin. 



It was during his career as a military surgeon that he 

 published his celebrated essay on " The Conservation of 

 Energy." 



The science of dynamics has been so long established, 

 that it is hardly conceivable that any addition to its 

 fundamental principles should yet remain to be made. 

 But in the application of pure dynamics to actual bodies 

 a great deal remains to be done. The great work for the 

 men of science of the present age is to extend our know- 

 ledge of the motion of matter from those instances in 

 which we can see and measure the motion to those in 

 which our senses are unable to trace it. For this purpose 

 we must avail ourselves of such principles of dynamics 

 as are applicable to cases in which the precise nature of 

 the motion cannot be directly observed, and we must also 

 discover methods of observation by which effects which 

 indicate the nature of the unseen motion may be mea- 

 sured. It is unnecessary here to refer to the labours of 

 the different men of science who, each in his own way, 

 have contributed by experiment, calculation, or specula- 

 tion, to the establishment of the principle of the conser- 

 vation of energy ; but there can be no doubt that a very 

 great impulse was communicated to this research by the 

 publication in 1847, of Helmholtz's essay " Ueber die 

 Erhaltung der Kraft," which we must now (and correctly, 

 as a matter of science) translate Conservation of Energy, 

 though in the translation which appeared in Taylor's 

 " Scientific Memoirs," the word Kraft was translated 

 Force in accordance with the ordinary literary usage of 

 that time. 



In this essay Helmholtz showed that if the forces 

 acting between material bodies were equivalent to attrac- 

 tions or repulsions between the particles of these bodies, 

 the intensity of which depends only on the distance, then 

 the configuration and motion of any material system 

 would be subject to a certain equation, which, when ex- 

 pressed in words, is the principle of the conservation of 

 energy. 



Whether this equation applies to actual material 

 systems is a matter which experiment alone can decide* 

 but the search for what was called the perpetual motion 

 has been carried on for so long, and always in vain, 

 that we may now appeal to the united experience of a 

 large number of most ingenious men, any one of whom, 

 if he had once discovered a violation of the principle, 

 would have turned it to most profitable account. 



Besides this, if the principle were in any degree incor- 

 rect, the ordinary processes of nature, carried on as 

 they are incessantly and in all possible combinations, 

 would be certain now and then to produce observable 

 and even startling phenomena, arising from the accu- 

 mulated effects of any slight divergence from the principle 

 of conservation. 



