1902.] 



Conductivity of Electrolytic Solutions. 



45 



" critical temperature " the water would, " independently of crystal- 

 lisation reach a lower limit of the liquid state," the mobility of the 

 ions being simultaneously reduced to zero. The actual existence of 

 such a sharply defined critical temperature appears to us to be some- 

 what improbable. We consider it more likely that in an overcooled 

 solution the relationship between conductivity and temperature, deter- 

 mined from observations above the freezing-point, would cease to hold 

 good in the neighbourhood of the conductivity zero, and that even at 

 considerably lower temperatures the electrolyte might still retain some 

 appreciable conductivity. 



We have obtained experimental evidence in support of this view 

 from a study of the conductivity of glass, which may be looked upon 

 as a typical example of an overcooled electrolyte. The accompanying 

 curve and table (fig. 2) represents a series of observations which we 



GLASS 



Temp. 



Cond. 



95° 



i 



106° 



3 



133° 



20 



139° 



25 



145° 



33 



/58° 



66 



164° 



100 



172° 



154 



179° 



226 



192° 



420 



204° 



769 



225° 



1754 



^L^y -O-CH^ I I 1 [ 



jocr~~TacP 146 6 Too 3 JeicP loo 5 Ho 5 £4o° 



Fig. 2. — Influence of temperature on the conductivity of glass. 



have made on the change with temperature of the conductivity through 

 the walls of a glass test-tube. The test-tube was half-filled with 

 mercury, and was placed inside a larger tube, also containing mercury, 

 and heated in a sand-bath ; the inner tube contained a thermometer, 



