HOLMAN. — THERMO-ELECTRIC FORMULA. 



207 



observations at 25°, 50°, aud 75° only. The range is too short, and 

 the intervals are too great to render the work of much service in 

 testing a genei-al formula, but if its accuracy is as high as about 

 0°.01, as it appears to be, this in j^art offsets the disadvantage. 

 Measurements of 2o e and t were made with four thermo-couples 

 with the results shown in Table VI. (international microvolts and 

 degrees centigrade on hydrogen scale). 



TABLE VL 



T/ie Avenarius equation was applied to these data by Chassagny and 

 Abraham in the form 



%e — at ■\- ht'. 



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

 these they computed the temperatures which the equation would 

 yield by insertion of the observed values "^e and 2o^e. These 

 values are given in Table VII., columns two and three. 



The exponential equation applied to these data for Fe - Pt be- 

 comes 



2f,e= 105.096 f 



6525.3 [Range 0° to 100° C.]. 



The values of t corresponding to the observed values Sf e and s'lf 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 



2^6= 19.2946 «*'^^^; 

 log %e = 0.97 059 5 log ^ + 1.28 543 6. 



The deviations are given in the table. 



