ICO JAMES CLE11K 



same laws ; and further, it may, I think, IKS shown that cither 

 method of viewing this subject, when carried HuHieiently far, 

 may l>e made the foundation of a mathematical theory which 

 would lead to the elementary principles of the other as conse- 

 quences. This theory would, accordingly, be the expression of 

 the ultimate law of the phenomena, independently of any 

 physical hypothesis we might from oth-r circumstances be led 

 to adopt That there are necessarily two distinct elementary 

 ways of viewing the theory of electricity may be seen from the 

 following considerations. . . ." 



In the pages which follow, Lord Kelvin develops 

 the consequences of an analogy between the conduc- 

 tion of heat and electrostatic action, which he had 

 pointed out three years earlier (IN42), in his paper on 

 " The Uniform Motion of Heat in Homogeneous Solid 

 Bodies," and discusses its connection with the mathe- 

 matical theory of electricity. 



The problem of distributing sources of heat in a 

 given homogeneous conductor of heat, so as to pro- 

 duce a definite steady temperature at each point or 

 the conductor is shewn to be malltcmnttcttlly identical 

 with that of distributing electricity in equilibrium, so 

 as to produce at each point an electrical potential 

 having the same value as the temperature. 



Thus the fundamental laws of the conduction ot 

 heat may be made the basis of the mathematical 

 theory of electricity, but the physical idea which 

 they suggest is that of the propagation of some effect 

 by means of the mutual action of contiguous particles, 

 rather than that of material particles attracting or 

 repelling at a distance, which naturally follows from 

 the statement of Coulomb's law. 



Lord Kelvin continues : 



