( 268 ) 

 CHAPTEE VIII. 



MAXWELL. 



SINCE the time of Descartes, natural philosophers have never 

 ceased to speculate on the manner in which electric and 

 magnetic influences are transmitted through space. About 

 the middle of the nineteenth century, speculation assumed a 

 definite form, and issued in a rational theory. 



Among those who thought much on the matter was Karl 

 Friedrich Gauss (b. 1777, d. 1855). In a letter* to Weber of 

 date March 19, 1845, Gauss remarked that he had long ago 

 proposed to himself to supplement the known forces which act 

 between electric charges by other forces, such as would cause 

 electric actions to be propagated between the charges with a 

 finite velocity. But he expressed himself as determined not 

 to publish his researches until he should have devised a 

 mechanism by which the transmission could be conceived to 

 be effected ; and this he had not succeeded in doing. 



More than one attempt to realize Gauss's aspiration was 

 made by his pupil Eiemann. In a fragmentary note,t which 

 appears to have been written in 1853, but which was not 

 published until after his death, Biemann proposed an aether 

 whose elements should be endowed with the power of resisting 

 compression, and also (like the elements of MacCullagh's 

 aether) of resisting changes of orientation. The former pro- 

 perty he conceived to be the cause of gravitational and 

 electrostatic effects, and the latter to be the cause of optical 

 and magnetic phenomena. The theory thus outlined was 

 apparently not developed further by its author ; but in a short 

 investigation^ which was published posthumously in 1867, he 



* Gauss' Werke, v, p. 629. t Riemann's Werke, 2 e Aufl., p. 526. 



J Ann. d. Phys. cxxxi (1867), p. 237 ; Riemann's Werke, 2 e Aufl., p. 288 ; 

 Phil. Mag. xxxiv (1867), p. 368. 



It had been presented to the Gottingen Academy in 1858, but afterwards 

 withdrawn. 



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