196 On the Temperatures of Conductors of Electiical Currents. 



In the second experiment, where the joint was cooled 1°*2 

 below the temperature of the atmosphere by the electricity fur- 

 nished by the action of a cold acid solution, on the interruption 

 of the current the temperature of the joint rose to 46°, or one 

 degree above that of the atmosphere. The second and third 

 experiments I repeated many times in order to satisfy myself of 

 their accuracy. In these experiments there is no effect on the 

 temperature of the joint which may not be accounted for by the 

 requirements of the batteiy for caloric, and the power which an 

 electrical current possesses of arranging temperatures in a con- 

 ductor composed of various materials. In the second experiment 

 it may be held that the cold water at 38° would, without the aid 

 of any galvanic current, reduce the temperature of the apparatus 

 below that of the atmosphere : this is an effect distinct from the 

 one noted ; for in the experiment in question there are portions 

 of the metallic circuit intervening between the joint B and the 

 cold solution which are above the temperature of the atmosphere ; 

 for example, where the electricity enters the bismuth, the tem- 

 perature for a current of this kind is 4° higher than where it 

 quits it at B, or 2°*8 above the temperature of the atmosphere. 



The normal temperature of the galvanic electricity derived 

 from the action of a battery is a point which the heat of the solu- 

 tion and atmosphere cannot altogether govern ; for there are 

 the chemical actions absorbing and evolving caloric, which must 

 also have their influence. In the Smee's battery I think it 

 extremely probable that the electricity comes from it at a tem- 

 perature lower than that of the apparatus or atmosphere when 

 these are uniform, as in the first experiment. 



The following repetitions of the second experiment show that 

 a cold water cell did not reduce the temperature like a cold acid 

 solution. 



Acid and 

 Pure water, water. 

 o o 



Temperature of apparatus and atmosphere . 45 45 



solutions 38 38 



joint after 15 minutes' action 44*8 43 



The small reduction in the temperature of the joint i^i the 

 pure water experiment is most probably due to the current given 

 by the water. I would have preferred the experiment without 

 this current, but to do so I must have destroyed a part of the 

 metallic contact of the plates in the cold water with the joint. 

 The difference, however, between the two experiments of 1°*8 is 

 an ample proof of the galvanic current from a cold solution 

 reducing the temperature of the joint, independently of the effect 

 of conduction from the joint to the water. 



