NOMOS. 89 



solid to become a fluid, and a fluid a gas. This 

 power is mysterious, but not unintelligible, and no 

 new principle of interpretation is required for the 

 explanation. 



In investigating the phenomenon of electrical heat, 

 we are struck, first of all, with one circumstance, and 

 this is that the degree of heat is appa- 

 rently proportionate to the inadequacy of 

 the conductor through which the current 

 is passing. With an ordinary current * ^jj 1 *" hy " 

 scarcely any heat is given out when a 

 thick wire is used as a conductor, but if this wire be 

 divided, and the ends connected by a piece of fine 

 wire, the latter wire is immediately heated, or even 

 fused. It is the same also when a strong current is 

 passed through a chain consisting of alternate links 

 of thick copper wire and thin platinum wire ; for in 

 this case the platinum links become red hot, while 

 the copper links are not appreciably affected except 

 by contact with the other links. That the evolution 

 of heat is in some degree connected with inadequate 

 conduction is also shown in an experiment which is 

 a modification of one which was originally used by 

 Mr. Grove in the illustration of another subject. 

 The instrument is an ordinary glass test-tube/across 

 which are carried two wires of different sizes, one 

 thick and the other thin. In using it, the tube is 

 filled with water, and the ends of each wire are 

 placed successively in connection with an appropriate 

 battery. A current is thus passed, first through one 

 wire, and then through the other, and the result is 

 that a great amount of heat is given out when the 



