1903.] 



Solutions at the Freezing-point of Water. 



333 



of stock solution were then added successively, the resistance being 

 measured after each addition. When, however, the solutions ap- 

 proached saturation, this procedure was reversed ; the stock solution 

 was first examined, and was then diluted by a weighed quantity of 

 water. 



Fig. 1. 

 (t full size.) 



Fig. 2. 

 (i full size.) 



The resistance cell was placed in a tin bath filled with melting ice. 

 At first, a thermometer was inserted in the cell, and the observations 

 postponed till its readings became steady at 0° centigrade ; but it was 

 soon found that the resistance itself gave a more sensitive and con- 

 venient means of thermometry. Measurements were taken at intervals 

 till they became constant ; the cell being always completely immersed 

 in ice, the result thus obtained shows the resistance at 0°. As an 

 example, the following numbers may be given : — 



12.45 

 12.55 

 1.12 

 1.16 

 1.18 



Eesistance. 

 2179 

 2191 

 2202 

 2202 

 2202 



It was intended to make up the solutions in the resistance cell 

 while it was immersed in the ice, but condensation of water from the 

 atmosphere was found to occur on the inside of the cold vessel when 

 stock solution was added. Before each addition, therefore, the cell 

 and its contents were raised to some temperature near that of the 



2 B 2 



