ft Bays from Radium by Solutions and Liquids, 611 



Fig. 3 gives the variations of activity for solutions of CaCl 2 

 of different thickness and concentrations. Curves 3, 5, 7, 

 and 11 give the activity observed for concentration of calcium 



Fig. 8. 



thickness 



(HQt 



>$. 



3.0- 



chloride corresponding to 3, 5, 7 and 11'75 gram-molecules 

 of \ CaCl 2 per litre of water respectively. For comparison, 

 the curves obtained for pure water and aluminium respec- 

 tively are added. 



Fig. 4 gives the variation of activity for solutions of cane- 

 sugar of different thickness and concentration. Curves 1, 3, 



Fig. 4. 



£.//,.& 



and 5 give the activity observed for concentrations of cane- 

 sngar corresponding to 1, 3, and 5 gram-molecules of sugar 

 per litre of water. The thickness of aluminium which cuts 

 down the activity to the same extent as a definite depth of 

 solution can be easily read off from the curved paper. 



2R2 



