200 



Article VI. 



On the Work performed and the Heat generated in a Conductor 

 by a Stationary Electric Current. By R. Clausius. 



[From Poggendorff's Annalen^ vol. Ixxxvii, p. 415.] 



1 HE following is a continuation of the paper contained in the 

 last part of these Memoirs (p. 1). The inquiry there insti- 

 tuted into the eiFects of a sudden discharge I have here endea- 

 voured to extend to the case of a continuous electric current. 

 At present, however, I will confine myself to an especial case. 

 I assume that the current, which I suppose to be constant, is 

 confined to a definite conductor, and regarding the latter I make 

 the following assumptions: — 1st, that the conductor suffers 

 neither mechanical nor chemical change by the passage of the 

 current ; 2ndly, that nowhere, within the conductor, a source of 

 electromotive power exists, which will be the case when the 

 conductor is composed of one material, in the same condition 

 throughout ; and 3rdly, that no inducing actions be exerted be- 

 tween it and other conductors or magnets. 



In this case the only effect produced by the electric current 

 is the heating of the conductor. The laws which regulate the 

 generation of heat, in the ordinary case where the conductor 

 possesses the form of a wire, have been empirically established 

 by Joule*, Lenzf and BecquerelJ, who have found that the 

 heat developed in a wire in the unit of time is proportional to 

 its resistance, and to the square of the intensity of the current. 

 Among the theoretic investigations connected with this subject, 

 I must particularly mention a paper by W. Thomson in the 

 Philosophical Magazine §. The results of this paper coincide, 

 as far as they refer to the same points, with those contained in 

 the present memoir, for in both of them the theoretic necessity 



* Phil. Mag., S. 3. vol. xix. p. 264, and S. 4. vol. iii. p. 486. 



t Poggendorff's Annalen, vol. Ixi. p. 44. 



: Aim. de Chim. et de Phys., S. 3. vol. ix. p. 21. 



§ S. 4. vol. ii. p. 551. 



