?30 



NATURE 



[July 9, 1891 



powers of hereditary rulers. In his view the narrow liberties 

 enjoyed by his subjects, under the Constitution reluctantly 

 granted by William IV. in 1833, were excessive and intoler- 

 able. He suspended the Constitution, and thereby called 

 forth vigorous protests from Dahlmann and other Pro- 

 fessors of the Hanoverian University. As a punishment, 

 seven of them— Dahlmann, Weber, the two Grimms (Jacob 

 and Wilhelm), Albrecht, Gervinus, and Ewald— were 

 ejected from their chairs, and Gervinus, Dahlmann, and 

 Jacob Grimm were even expelled from the country. From 

 this time Weber lived for some years in retirement, but 

 in 1843 he accepted the Professorship of Physics in 

 Leipzig (in succession to Fechner), and in 1849 he returned 

 to his former position in the University of Gottingen. 

 He was in Gottingen at the time of his death. 



Wilhelm Weber's eldest brother, Ernst Heinrich, was 

 the celebrated Professor of Anatomy and Physiology at 

 Leipzig. He was born at Wittenberg in 1795, and died 

 at Leipzig in 1878, having been elected a Foreign Member 

 of the Royal Society of London in 1862. The youngest 

 of the three brothers, Eduard Friedrich, was also highly 

 distinguished as an anatomist, and held office for many 

 years in the University of Leipzig. 



Weber's first contribution to science at once took rank 

 as a scientific classic, a position it is likely to keep for 

 many years to come. This was " Die Wellenlehre auf 

 Experimente gegriindet," a volume of 574 pages, and 

 18 copper plates, nearly all engraved by the authors, 

 published in 1825 by the brothers Ernst and Wil- 

 helm Weber, and embodying the results of number- 

 less original experiments and observations. One of the 

 most striking results of these investigations was the dis- 

 covery that, when a regular series of waves follow each 

 other along the surface of water, the particles at the 

 surface describe vertical circles whose plane is parallel to 

 the direction of propagation of the waves, and those 

 lower down ellipses of which the vertical axis becomes 

 smaller and smaller with increasing depth. As to the 

 composition of this work, the authors say that it grew up 

 as the result of such constant and intimate communica- 

 tion between them with regard to all parts, that it is 

 impossible to assign to either of them the separate 

 authorship of any distinct portions. 



For several years Weber continued to occupy himself 

 mainly with questions of acoustics, on which he published 

 various papers of importance. In 1833 he published, in 

 conjunction with his brother, Eduard Friedrich, a me- 

 morable investigation into the mechanism of walking 

 "Mechanik der menschlichen Gehwerkzeuge"). 



But it is chiefly by his magnetic and electrical re- 

 searches that Weber's place in the history of science is 

 marked. These are contained for the most part in the 

 " Resultate aus den Beobachtungen des magnetischen 

 Vereins," published by Gauss and Weber from 183710 

 1843, and in Weber's " Elektrodynamische Maassbestim- 

 mungen" (published in collected form in 1864, though 

 the first paper dates from 1846). In this series of papers 

 Weber showed fot the first time how methods of absolute 

 measurement, analogous to those which Gauss had very 

 shortly before shown to be applicable to magnetic 

 measurements, could be extended into the region of 

 electricity. Before this time Ampere's splendid dis- 

 coveries as to the laws of the mutual forces between 

 magnets and conductors traversed by electric currents, 

 or between two such conductors, had been made known, 

 and G. S. Ohm had established once for all the relations 

 between electrical resistance, electromotive force, and 

 strength of current ; but, nevertheless, there was as yet 

 no settled system for the measurement and statement of 

 electrical quantities themselves. Until Weber's time 

 electrical measurements were merely comparisons be- 

 tween magnitudes of the same kind : the resistance of 

 one conductor could be compared with that of a par- 

 ticular piece of wire, the electromotive force of one 

 NO. 1 132, VOL. 44] 



battery could be compared with that of another ; but 

 that the value of an electrical quantity could be stated 

 without reference to any quantity of the same kind, 

 and in terms not involving any physical constants 

 but the units of length, time, and mass, was as 

 yet an entirely new conception. Weber, however, not 

 only showed that such a system of measurements 

 was theoretically possible, but in a series of most 

 masterly experimental investigations he showed how it 

 could be practically carried out. Our countryman Sir 

 William Thomson was one of the very first men of 

 science to recognize the fundamental character and far- 

 reaching importance of Weber's work ; and owing mainly 

 to his clear-sighted advocacy of the absolute system of 

 measurement, this system was from the first adopted as 

 the basis for the operations of the British Association 

 Committee on Electrical Standards, appointed originally 

 in 1862. This system has now become so familiar to 

 electricians, and is taken so much as a matter of course, 

 that it requires some mental effort to recall the state of 

 science when it did not exist, and to appreciate the intel- 

 lectual greatness of the man to whom it is due. If we 

 consider method and point of view, rather than acquired 

 results, it is not too much to say that the idea of absolute 

 measurements, underlying as it does the conception of 

 the conservation of energy, constitutes the most charac- 

 teristic difference between modern physics and the 

 physics of the early part of our century. And to no one 

 man is so large a share in this great step due as to 

 Wilhelm Eduard Weber. 



Weber was a Corresponding Member of the Institute 

 of France. He was elected a Foreign Member of the 

 Royal Society in 1850. G. C. F. 



A SOUVENIR OF FARADAY. 



THE following letter, written by an old friend of 

 Faraday's and of mine, long since dead, may 

 interest your readers, now that we are celebrating the 

 centenary of Faraday's birth. It came in reply to one 

 in which I asked Mr. Ward's assistance in preparing 

 an obituary notice of Faraday for the Chemical News. 

 William Crookes. 



Cornwall, August 30, 1867. 



Dear Crookes,— I should be proud indeed to be the 

 spokesman of the chemical world in doing honour to 

 Faraday's illustrious name on the occasion of his acces- 

 sion to immortality. 



But I should not dare to meddle with the laurels on so 

 august a brow, without many days and nights of earnest 

 research and meditation, to fit me for summing up, with- 

 out omission, the splendid list of his imperishable 

 labours. 



Only in this reverential spirit of earnest solicitude to 

 do aright, which is, if I mistake not, the philosophical 

 counterpart of prayer — of the religious feeling — could so 

 solemn a duty be fitly undertaken. 



Only with the aid of other minds, kindred with Fara- 

 day's in genius, and filled with the light of his manifold 

 discoveries, could any one man's mind become an ade- 

 quate mirror to reflect the gigantic Shadow that has just 

 passed to its place in futurity. 



For the present it is my fate to fulfil much humbler 

 duties— which, having undertaken, I have no right to set 

 aside. For duty must still be done, even when such 

 appeals as yours set the wings of the caged lark trembling, 

 and point him upwards to his barred out home. 



I must remain, therefore, a unit among the millions 

 whose hearts do silent homage to the illustrious dead ; 

 and can but watch from afar the starry coronation of 

 which you invite me to be minister. 



So best, perhaps. For, after all, the name and fame of 



