﻿on the Contact of different Metals. 23 



If from these experiments the quantities of heat (x) be calcu- 

 lated on the assumption that, as theory requires, they are propor- 

 tional to the intensity of the current, we get the formula 



#=19-82 tg.v, 



in which v is the angle of deflection of the tangent-compass. 



From this we obtain the following calculated values compared 

 with the observed ones : — 





Calculated. 



Observed. 



Experiment 1. . 



. . 19*2 



18-6 



2. • 



. . 12-6 



12-9 



3. . 



. . 19-8 



19-4 



4. . 



. . 12-1 



12-5 



Experiment 5. — The same wires as in the foregoing experi- 

 ments. The liquid in the glass tube consisted, in this as in all 

 the following experiments, of cognac. The deflections became 

 thereby smaller than before. 



Deflections. 

 18-3 

 15-8 

 20-0 

 16-8 

 15-5 



Mean . . 17'3 

 Intensity of the current = tg. 44° 45'. 

 Experiment 6. — The same wires. 



Deflections. 

 11-2 

 10-7 

 12-2 

 117 

 13-5 



Mean . . 11*9 



Intensity of the current = tg. 33° 10'. 



If the last two results be calculated by the formula 

 x = 17*83 tg. v, we obtain in 



Calculated. Observed. 



Experiment5. . . . 177 17'3 



6. . . . 117 11-9 



Experiment 7. — The wire consisted now of platinum and cop- 

 per soldered with tin ; the former was 1 millim. in diameter. 

 When the positive current went from the platinum to the copper 

 at the place of contact, there was a cooling. 



