COBALT CHLORIDE AND CALCIUM CHLORIDE. 

 TABLE 102. 



199 



* Interpolated from the table given by Jones and Bassett. Amer. Chem. Journ., 33, 

 546 (1905). 



The solution of concentration 3.143 was dark blue at room temperature, 

 but red near its freezing-point. This phenomenon has frequently been 

 observed before. 



The most concentrated member of the series tabulated not only turned red, 

 but the salt separated out when an attempt was made to determine its 

 freezing-point. Table 103 contains the electrical conductivities, at zero 

 degrees, of the solution of cobalt chloride and calcium chloride. The data 

 are expressed in reciprocal ohms and reciprocal centimeters. 



Since the data for the electrical conductivities of standard solutions are 

 usually expressed in terms of the reciprocal of the Siemens mercury unit, 

 it may not be superfluous to explain how the reduction to reciprocal ohms 

 and reciprocal centimeters is effected. The ratio of the Siemens unit of 

 resistance to the ohm is as 1 1.063; hence, to change the number representing 

 the value of the conductivity of a given solution from reciprocal Siemens 

 units to reciprocal ohms, the number must be multiplied by 1.063.* Fur- 

 ther, reduction to reciprocal centimeters is accomplished by dividing the 

 number expressing the conductivity in reciprocal ohms by the product of 

 1,000 into the "volume" of the solution. For the sake of illustration, for a 



* In certain cases the reduction factor is 1.069. 



