thermo-electric Interpolation Formula. 



479 



its accuracy is as high as about o, 01, as it appears to be, this 

 iii part offsets the disadvantage. Measurements of Xo e and t 

 were made with four thermo-couples, with the results shown 

 in Table VI. (international microvolts and degrees centi- 

 grade on hydrogen scale). 



The Avenarius equation was applied to these data by Chas- 

 sagny and Abraham in the form 



2,1 e = at + bt*. 



They evaluated the constants from the 50° and 100° data. 

 With these they computed the temperatures which the equa- 

 tion would yield by insertion of the observed values So 5 e and 

 2J° e. These values are given in Table VII., columns 2 

 and 3. 



The exponential equation applied to these data for Fe — Pt 

 becomes 



2o«=105-096 * * 7360 - 6525*3 [Range 0° to 100° C.]. 



The values of t corresponding to the observed values 2o 5 e 

 and So 5 e are given in Table VII. It has not seemed for the 

 present purpose worth while to make similar computations 

 for the other couples, as they would not materially affect the 

 inferences to be drawn. 



The logarithmic equation yields 



2U = 19'2946 J * 970595 ; 



log 2S 6=0-970595 log * + 1-285436. 



The deviations are given in the Table. 



Table VII. 



Couple. 



Avenarius. 



Exponential. 



Logarithmic. 



t. 



St. 



t. 



St. 



6 

 mv. 



100 S/e 

 per cent. 



St. 



S 

 mv. 



Fe-Ou 



Fe-Pt Eh.. 



Fe-Ag 



Fe-Pt .... 



Fe-Cu 



Fe-Pt Eb.. 



Fe-Ag 



Fe-Pt 



24-88 



24-885 



24-87 



24-87 



7513 



75-135 



75135 



75135 



+0-12 

 0-115 

 0-13 

 0-13 



-0-13 

 0135 

 0135 

 0-135 



o 



24-80 

 75-15 



o 



+0-20 

 -0-15 



-26 



+2-5 



-0-037 

 +0-032 



o 

 +0-52 

 -0-26 



-6-7 

 +4-3 



