222 



ELECTROCHEMISTRY 



puted from all of the experimental data by Gauss' method of 

 least squares. Inserting these values of the constants and the 

 experimental values of x in equation (iii), the " calculated" 

 values of ra are computed. In the third column of the tables 

 is given the ''Degree of Dissociation" of the salt calculated from 

 the ratio of Ax in equation 3 to the " calculated" value of ra. 



The conductivity of the distilled water (usually not in excess 

 of 4 X 10~ 6 ) is subtracted from each of the observed conductivities. 



TABLE I 



Sodium Caseinate. Approx. neutral to Litmus. Approx. 50 X 

 Equivalents NaOH per gram. Temperature 25 degrees 

 A = 19.51 B = 9611 



TABLE II* 



Ammonium Caseinate. Approx. neutral to Litmus. Approx. 50 X 10~ 5 

 Equivalents NH 4 OH per gram. Temperature 25 degrees 

 A = 16.27 B = 6188 



* T. Brailsford Robertson (8). The exact proportion of base to casein in these experiments is 

 not certain, since the original solution which was diluted to yield the remainder was made up by 

 shaking up an . 02 N solution of the base with excess of casein under the erroneous belief (Cf . T. 

 Brailsford Robertson (6) (8) (11)) that the maximum amount of casein which a given concentra- 

 tion of a base would dissolve, when shaken up with excess of casein, was that with which it will 

 unite to form the "neutral" caseinates; i.e., containing 50 X 1Q- 5 equivalents of base per gram. 

 Since, however, casein dissolves rapidly up to this point and very slowly afterwards the composi- 

 tion of the salt formed was probably very nearly that indicated at the head of the tables. More- 

 over the solutions were tested and found to be neutral to litmus. The last observation in Table I 

 and the last but one in Table II are omitted in computing the values of the constants. 



