172 



ELECTROCHEMISTRY 



conductivity of a solution of the neutralized KOH minus the 

 conductivity of the caseinate. If we subtract this quantity 

 (xi — x) from the conductivity of the neutrahzed KOH, therefore, 

 we obtain the conductivity of the caseinate itself. Now in these 

 solutions, as determined by the gas-chain, the concentration of 

 neutralized KOH was 0.00993, and the conductivity at 30 degrees 

 of a solution of free KOH of this concentration would be 28C X 10~^ 

 reciprocal ohms. Subtracting Xi — x from 280 X 10~^, therefore, 

 we obtain the conductivity, in each of the solutions investigated, 

 of the caseinate itself. In the following table some experimental 

 results are given. In the first column is given the concentration 

 of KCl which was present in the solution of caseinate; in the 

 second the conductivity (= Xi) of the solution containing no 

 casein; in the third the conductivity (= x) of the solution con- 

 taining casein; in the fourth the conductivity (= 280 X 10~^ — 

 {xi — x)) of the caseinate itself; in the fifth the deviation of this 

 conductivity from its average value in the different solutions; 

 in the sixth the experimental error of the conductivity meas- 

 urement itself, exclusive of any possible deviations arising out 

 of errors in weighing, measurements of volume, or decomposition 

 of the casein. 



It is evident that the estimates of the conductivity of the 

 caseinate itself which were thus obtained are appreciably con- 

 stant, the deviation from the average being irregular and less or 

 only very slightly greater than the purely metrical error of the 

 observation. In other words, whether the concentration of KCl 

 in its solution is 0.00 or 0.03 the share taken by the potassium 

 caseinate itself in conducting the current is the same within the 

 experimental error, that is, at the very highest estimate, within 

 10 per cent. 



Now suppose that potassium caseinate, containing this pro- 

 portion of potassium, yields, on dissociation, only one potassium 



