46 Conductivity of Aqueous Solutions. Part II. 



In order to compare the conductivity values at different temperatures, 

 it is desirable to correct those directly measured for the change in concen- 

 tration produced by the expansion when a given solution is heated. The 

 values in table 8, which, owing to this expansion, refer at different tem- 

 peratures to somewhat different concentrations, as is there indicated, have 

 been reduced to the nearest round concentrations, by a graphic interpola- 

 tion with the help of the nearly linear function = j- K(CA) - 5 (Sec 



A A 



section 17.) The so-reduced values are presented in table 9. 



In the subsequent stages of these researches various other measure- 

 ments of the conductivity of sodium and potassium chloride solutions have 

 been made by other experimenters, namely, by A. C. Melcher, by G. W. 

 Eastman, and by H. C. Cooper. This has been done partly as a control 

 and partly in order to complete this first series of measurements. The 

 details and original data of these experiments will be presented in the later 

 articles of this series ;* but in order to simplify and shorten the discus- 

 sion of the results we have included all of their final values, together with 

 our own, in table 9. Our values are indicated by adding the letters N-C 

 to the data, those of A. C. Melcher by the letter M, of G. W. Eastman by 

 the letter E, and of H. C. Cooper by the letters Cp. The best final values 

 which we have derived by combining all these data, a double weight being 

 usually assigned to the later determinations, are printed in black type in 

 the table. The values at 18 are those of Kohlrausch and Maltby. The 

 values at for potassium chloride are means derived from the closely 

 concordant determinations of Whethamf and of Kahlenberg4 All the 

 other data in the first table for potassium chloride were obtained by G. W. 

 Eastman in this laboratory. The values given in parentheses for zero 

 concentration were obtained by graphic extrapolation with the help of the 



1 1 



empirical formula - = K(CA) m , as described in section 17. 



A A 



In this table, as in all those containing final values throughout this publi- 

 cation, the concentration is expressed in milli-equivalents per liter, using as 

 atomic weights the values given by the International Commission for 1905 ; 

 the temperature is expressed on the hydrogen-gas scale, using for the 

 reduction to this scale at 218, 281, and 306 the values found for the 

 boiling-points of naphthalene and benzophenone by Jaquerod and Wass- 

 mer; and the equivalent conductance is expressed in reciprocal ohms and 

 refers to a concentration at the temperature under which it stands equal to 

 the value given opposite to it in the first column. 



*See section 41, Part IV, and section 54, Part V. 

 fZ. phys. Chem., 33, 351 (1900). 

 $J. Phys. Chem., 5, 348 (1901). 



