492 Mr. W. Stiles and Dr. F. Kidd. The Comparative 



action brings about exosmosis which causes the subsequent rise in conduc- 

 tivity. The loss of turgidity of the discs corresponds with this. 



Table IV. — Carrot in Solutions of various Sulphates of Concentration N/50. 



Potassium 

 sulphate. 



Sodium sulphate. 



Magnesium 

 sulphate. 



Zinc sulphate. 



Aluminium 

 sulphate. 





Change 





Change 





Change 





Change 





Change 



Time 



in 



Time , 



in 



Time 



in 



Time 



in 



Time 



in 



in 



electrical 



in 



electrical 



in 



electrical 



in 



electrical 



in 



electrical 



hours. 



con- 



hours. 



con- 



hours. 



con- 



hours. 



con- 



hours. 



con- 





ductiyity. 





ductivity. 





ductivity. 





ductivity. 





ductivity. 



0-5 

 1 -0 

 14 -25 

 25 -25 

 43 -0 

 64-5 



-176 

 -183 

 -205 

 -215 

 -208 

 -273 



0-5 

 1 -0 

 14 -5 

 25 -5 

 43-25 

 64-75 



- 54 



- 48 



- 4 



- 34 



- 66 

 -117 



0-5 

 1 -0 

 14-5 

 25 -0 

 43 

 64 -5 



-37 

 -37 

 -26 

 -26 

 -12 

 -33 



0-25 

 0-5 

 14 -0 

 25 -0 

 43-0 

 64-5 



- 13 



- 20 

 + 180 

 -H368 



+ im 



+ 929 



0-25 

 0-5 

 14-0 

 25 -0 

 43 -0 

 64 -5 



+ 102 

 + 139 

 + 381 

 + 451 

 + 644 

 + 816 



In the case of aluminium this explanation does not hold as the discs are 

 perfectly healthy and turgid at the end of the experiment. We have 

 suggested provisionally in a former paper that the aluminium ion is absorbed 

 much more rapidly than the sulphate ion, and that the consequent replace- 

 ment of the aluminium ion by one of a higher mobility, as, for instance, 

 hydrogen, accounts for the increase of conductivity in this case. This point 

 will be dealt with in more detail in a later section of this paper. 



lOOOi i . — — — , 



I , , J 



25 50 75 



TIME IN HOURS 



Fig. 3. — Carrot in Solutions of various Sulphates of Concentration N/50. 



