IN WATER AND CERTAIN ORGANIC SOLVENTS. — DAVIS. 43 



Conductivity m-easurements were made at three tempera- 

 tures, 25°C, 18°C, and 0°C. Tite first two were obtained in 

 a bath, stirred by an electric motor, and with gas supply 

 regulated by a thermostadt. The temperature of this bath 

 remained steady to a tenth of a degree. 



The 0° bath consisted of two dishes. The outside one was 

 filled with cracked ice, moistened with distilled water and the 

 inner one was filled with about equal volumes of ice and water. 

 The temperature of the cell immersed in the ice in the inner 

 vessel remained steady at 0°C. 



The cell used was about three inches in height and two in 

 diameter. The electrodes were platinized. The constant of 

 this cell was checked every two or three days by a standard 

 j)otasium chloride solution. This solution was made from 

 a sample prepared from Merck's C. P. chloride ''for 

 analytical purposes" by recrystallization four times from water. 

 It was then dried in a desiccator for four or five weeks. For 

 this sample I am indebted to Mr. C. B. jSTickerson of the 

 Chemical Department at Dalhousie College. 



Preparation of Solutions. A weighed amount of fuchsine 

 was placed in a calibrated (400 cc. or 100 cc.) flask and dis- 

 solved, and liquid added to the 400 cc. mark. It was then 

 diluted, by the addition of pure water, to make a _i^ ISJ". solution. 

 In most cases the dilution required was from 2-4 cc. per 400. 

 Some trouble and inaccuracy is caused by froth on the surface 

 of the liquid. 



20 cc. of this solution was placed by a pipette in the cell 

 and further dilution carried out in the cell itself by two 10 cc. 

 pipettes, one for withdrawal and one for delivery. All these 

 pipettes were standardized. 



Notation. 



V = jSTo. of liters which contain 1 mol. of dissolved solute 

 (C^H,oN3Cl = 337.4 gr.) 



T= Temperature in Centigrade degrees. 



