ON THE OSMOTIC PRESSURES OF CALCIUM FERROCYANIDE SOLUTIONS. 331 



solutions decreased slightly in resistance with lapse of time, except the most dilute of 

 all, which increased with the time.* In each case a time coefficient was determined 

 by experiment, and the resistances given in the tahles are the resistances the solutions 

 would have had immediately after being made up. 



It was also noticed that, with the low-resistance cell, the rate of alternation of 

 current had a perceptible effect on the resistance ; a great number of experiments 

 were made to determine the cause of this, but without result. It was, therefore, 

 decided to make all measurements at a speed which, on the whole, gave the most 

 consistent results. 



Results for Calcium Ferrocyanide. 



The results for the calcium ferrocyanide are collected in the following table. The first 

 seven lines refer to solutions whose constants were determined in the high-resistance 

 cell and the remainder refer to the low-resistance cell. 



TABLE VII. 



The equivalent conductivities of the stronger solutions are plotted against the 

 concentrations in diagram 1, and those of the very dilute solutions are plotted against 

 the cube root of the concentrations in diagram 2 ; the latter curve when extrapolated, 

 as shown by the dotted lines, to infinite dilution gives the probable limits between 



* The greatest decrease observed was 03 per cent, per hour, while the increase in the most dilute 

 solution of the calcium salt was 0- 10 per cent, per hour, and for the strontium salt 0-14 per cent. 



2 U 2 



