Thermoelectric Position of Carbon. 123 



Hence the thermoelectric power of the couple is 

 e A = +577 + 3-92 x* C.G.S. units, 



t denoting the mean temperature of the joints. The direction 

 of the current would be from Pt to C across the hot joint. 



Curve B. 

 Taking an equation to the curve of the same form as that 

 just used, T= -140° C. and K = -00406 best satisfy obser- 

 vation. 



Table I. 



X. 



a. 



9; 



Calculated. 



Observed . 



o 

 30 

 40 

 50 

 60 

 70 

 80 

 90 

 100 

 110 



9 ? 75 



9-82 



9*85 



>> 



9-9 



159 

 24-4 

 33-4 

 429 

 52-9 

 632 

 74-2 

 85-5 

 97-4 



I 

 15-8 

 24-2 

 334 

 431 

 530 

 63-4 

 74-1 

 85-1 

 97 7 



Table II. 







y- 



X. 



a. 











Calculated. 



Observed. 



O 



30 



o 



9-6 



13-5 



132 



40 



965 



20*3 



20 3 



50 



970 



27*8 



27-8 



60 



9-75 



35-7 



35-7 



70 





438 



440 



80 





52-6 



52-7 



90 



9-80 



61-9 



61-9 



100 



)) 



717 



71*4 



110 



9-85 



81-8 



82-4 



120 



» 



92-6 



916 



Table II. exhibits the agreement of the calculated and 

 observed values of y w r hen these constants are inserted in the 

 equation to the curve. To calculate E.M.F. (E B ) ? the data 

 are the same as w T ere used in the calculation of E A? except 

 that the resistance in the primary circuit was 259*6 ohms. 



... E B = -00406 x 1-03 x 10 8 x ^^( A .-a)(l40 + ^) 

 = S>960e- a)(l40 + ^|^ C.G.S. units. 



