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



electromotive force. Because it can be assumed that the 



entire resistance is included in No. 1, a quantity of galvanic 



E— e 

 heat = — 5 — x 23900 is developed there. The sum of the 



d 

 actions of these three sources of heat becomes k — 23900 — . 



e 



If this quantity of heat be compared with that which was ob- 

 tained in the first case (a), the comparison shows that, through 

 the insertion of the voltameter, the calorimeter No. 1 suffered 



(> 

 a loss of heat =23900 j, although it cannot have given up its 



heat to that calorimeter. A source of heat is produced in 



No. 2 by the electromotive force of polarization acting in the 



opposite direction to the current. The heat thus produced is 



e 

 = 23900 j units — that is, equal to the amount of heat lost by 



calorimeter No. 1. But the quantity a of heat is consumed 

 by the chemical decomposition. The change of heat in calc- 



rimeter No. 2 therefore becomes 23900 --, —a, 



a 



In Favre's- experiment it was shown that the loss of heat in 



(23900-1 J in calorimeter No. 1, when the voltameter contained 



water, amounted to 54235 units. The consumption a of heat 

 in the decomposition of the water amounted to 34204. The 

 difference between these two numbers is 20031. Calorimeter 

 No. 2, as mentioned above, indicated for this difference 20335 

 heat-units. 



When the voltameter contained the copper solution, the 

 loss of heat in calorimeter No. 1, according to Favre's experi- 

 ment, came to 38580 units. The heat-consumption on the 

 decomposition of the salt of copper amounted, according to 

 the experiment, to 26568. The difference between the two 

 numbers becomes therefore 12012. Calorimeter No. 2 should 

 consequently have shown a production of 12012 units of heat ; 

 but the direct reading ga\ ? e 12445. The difference, however, 

 between calculation and observation is not too great to be 

 ascribed to unavoidable errors of observation. A reason why 

 the voltameter No. 2 indicated in both cases a somewhat 

 higher production of heat than the calculation required is, 

 that in the calculation the resistance of the voltameter was 

 supposed equal to nil, which cannot be quite correct. There 

 was therefore really present in the voltameter a small source 

 of heat which was not taken into account, namely the galvanic 

 heat-development ; and from this was doubtless chiefly derived 



