346 



ON THE SURFACE TEIs T SION AND 



these in the proportions as to volume requisite to prevent 

 change of ionization on mixing, and then to measure and cal- 

 culate the specific gravity of the mixture. For the exact mode 

 of determining the ionization coefficients, concentrations and 

 volumes of the four simple solutions to be mixed, I may refer to 

 my paper cited above. All the data required for the calcula- 

 tions are given in Table VI, together with the calculated and 

 observed values. The concentrations of solutions and specific 

 gravities are expressed in terms of the same units as in pre- 

 vious tables. The column headed " volumes " contains the 

 volumes in c. c. of the Potassium and Sodium Chloride solutions 

 mixed with 25 c. c. each of the sulphate solutions. 



TABLE VI. 



The above table shows that in all except the last solution 

 examined the differences between the observed and calculated 

 values are either within or but little beyond (in three cases 

 within and in six a little beyond) what I consider my possible 

 error of observation. They are also about equally divided as to 

 sign. Considering the large number of sources of error involved 



