430 Prof. E. Edlund on the Thermal Phenomena of the 



arising in the pile cannot pass over into galvanic heat, but a 

 part of it is expended for the mechanical work necessary for 

 generating the electromotive forces of polarization and the 

 chemical decomposition in the cell. We can imagine this 

 brought about by the store of chemical heat requisite for 

 this work being carried by the current from the pile into 

 the decomposition-cell, where it is employed for the purpose 

 mentioned. Consequently no other change of temperature 

 can arise in the decomposition-cell than that which is occa- 

 sioned by the passage of the current through the electrolytic 

 liquid. The heat generated in the decomposition-cell must 

 therefore be equal to that which is produced when the current 

 passes through a metallic conductor the resistance of which is 

 equal to that of the liquid. Now, as by direct measurement 

 the quantity of heat produced in the decomposition-cell has 

 been found greater than the galvanic, the cause of this has 

 been sought in the secondary chemical processes which may 

 take place there and are independent of the current. 



2. I have already, some years since *, given another expla- 

 nation of the thermal phenomena in question. It was, in 

 brief, the following : — If the current does no external work, 

 its total action consists in calling forth heat in the conduc- 

 tor through which it passes. After the current has ceased, 

 no other products of the activity of the pile are found but 

 the chemical changes in the pile and the heat which has 

 arisen, partly in the pile itself, and partly in the conductors. 

 It is evident, however, that the amount of this heat must be 

 equivalent to the chemical changes ; that is, in other words, 

 the quantity of heat generated must be exactly equal to that 

 which would have resulted from the same chemical changes if 

 no current had taken place; for otherwise either chemical 

 work or heat would have been obtained out of nothing. The 

 current has therefore, upon the whole, generated no heat at 

 all ; its total heat-production is equal to nil. But we know 

 that the current does a certain amount of mechanical work 

 in order to overcome the resistance of the galvanic conduc- 

 tion ; and this work changes into heat. Therefore the cur- 

 rent brings forth in the conduction an actual production of 

 heat. But, because the total heat-production of the current 

 must be equal to nil, this can only happen through a con- 

 sumption of heat occurring at some place or other in the 

 conduction ; and of course the place can be no other than 

 that where the electromotive force has its seat. We conse- 

 quently arrive at the result that, in order to produce the cur- 



* Ofversigt af K. Vetenskaps Akademiens Foi-handlingar, 1869; Pogg. 

 Ann. vol. cxxxvii. p. 174. 



