[m'lennan & KENNEDY] RADIOACTIVITY OF POTASSIUM- 



17 



The results obtained with potassium sulphate are recorded in 

 Table II, and a curve representing them is shewn in Fig. 3. From 

 these it will be seen that the saturation currents steadily increased 

 with the thickness of the layer of salt exposed until a thickness of 

 2.5 cm. was reached, when the current assumed a steady value and 

 remained the same for greater thicknesses. 



Additional observations were made with the halogen salts of 

 potassium and still others with 2 samples of potassium cyanide, one 

 with a sample of potassium hydroxide and one with a second specimen 

 of chloride of potassium. The results of these measurements are given 

 in Tables III and IV, and curves representing them in Figs. 4 and 5. 

 From all the results recorded it will be seen that layers of the different 

 salts between 2 and 3 mms. were amply sufficient to give the maximum 

 saturation currents. 



TABLE II. 



ACTIVITY OF POTASSIUM SULPHATE. 



Sec. Ill,, 1908. 2, 



