619 



out with a solution of the coiicenlration 1 ni. Mol. KCI per Liter. 

 The hattery was tilled March 11'''. P indicates the pi-essurc, E the 

 current potentials. 



From this we notice that the ajiparatus acted splendidly. The 

 potential per cm. mercury pressure has each day a constant value, 

 but varies the first two days. On tlie third day the terminal value 

 is attained. 



4. MeasaremeMts. In this paper a series of measurements is com- 

 numicated, the object oi' which was to ascertain the influence of 

 some solutions which differed in the valency of the cation. Therefore 

 solutions^ of the chlorides of K' , Ba", and Al'" were used. As 

 solvent was always used so-called ''conductivity water". The very dilute 

 solutions were made by diluting a standard solution. All measures 

 used in this investigation were carefully calibrated or recalibrated. 



In order to shorten the time of these tedious measurements 

 they were all executed 20 hours after filling the cell. True, the 

 constant terminal value is then not yet attained, but the difference 

 is comparatively small and the error inti'oduced is the same in all 

 measurements. Moreover, the inaccuracy caused thereby is without 

 influence on the tendency of the conclusions presently to be drawn, 

 in itself a good reason for proceeding to this measure of enormous 

 time saving. Moreover, several sets of flasks were used, in such a 

 manner however that, for instance, all the KCi solutions were 

 measured in the same set. Finally, the sets were compared mutually 

 in which the solution of 100 (i Mol. (micwmol^^/^^g^ miWinioV) KCI 

 p. L. served as comparison liquid. With both apparatus was found 

 exactly the same value for the potential per unit of pressure. 



In the subjoined tables, the concentrations in the first column are 

 given in ft mols. p. L. ; in the second column is found the current 

 potential E in millivolts per unit of pressure (cm. of mercury) under 

 which the liquid was forced over. This value is always the mean 

 of two or more measurements whose differences were of the order 

 of those in Table 1 (generally much less than those). 



When in the tables no sign is indicated at the potential value, 

 the condition (as with pure water) is such that the electrode Ej in 

 fig. 1 is negative. In the AlCl^ solutions a change of poles took 

 place, hence the potentials following are indicated by -|-- 



The results of the tables II to IV are represented graphically in 

 fig. 2. Fig. 3 also gives the curve for /I/C/3 on a larger scale. 



