NOYES AND COOLIDGE. 



ELECTRICAL CONDUCTIVITY. 



199 



the measurements (Cell I) was accidentally broken, and a new one had 

 to be substituted for the rest of the work. After making three experi- 

 ments with the new cup, the platinum lining of the lower part of the 

 bomb had to be removed and repaired, and this operation changed the 

 cell-constant. The term Cell II a will be used to characterize the bomb 

 as it was in these first three experiments with the new cup, and the term 

 Cell II as it was in all subsequent work. With these exceptions, the 

 cell-constant calculated from measurements made at widely different 

 periods did not vary throughout the work. Even when the electrode 

 was removed in case of a leak, and then replaced, it did not make any 

 measurable difference, as was, indeed, to be expected, since the value 

 of the cell-constant is so largely determined by the dimensions of the 

 quartz cup. The values of the cell-constants, with the solutions from 

 which they were derived, are as follows : 



TABLE III. 

 Cell-Coxstants. 



The original data from which these were calculated are all given in 

 Table VI. Each cell-constant value is the mean of all of the values 

 calculated from all of the experiments on the solution in question at 2G°. 



The values derived from the 0.002 normal solutions are not included 

 in tie; means, because, owing to the higher dilution, they are probably 



