Absorption of Rontgens Rays by Solutions of Metallic Salts. 419 



sponding to the thin edge of the wedge in the photographing apparatus, 

 in terms of the whole length of the wedge. 



Results. 





"Weight (in grams) of 

 anhydrous salt in 

 100 c.c. of normal 

 solution. 



Thickness (in mm.) of 

 normal solution neces- 

 sary to produce the 

 same absorption as 

 20 mm* of water. 



Bromides : — 









92 



6-2 





10-0 



5-5 





10*3 



5-0 





10-8 



4-8 





13 6 



4-1 





11 9 



4-1 





9-8 



4-1 



■ 



11 -s 



2-6 



These results were obtained by method 2. The absorption both of these and of 

 the iodides is rather too high to make great accuracy possible. 



Chlorides : — 

 Lithium 

 Sodium 

 Potassium . . 

 Ammonium . 

 Magnesium. . 

 Calcium 



Cobalt 



Iron (Ferric) 



Nickel 



Zinc 



Copper 



Strontium. . . 



Barium 



Cadmium . . . 

 Lead 



Iodides : — 

 Magnesium. . 

 Calcium 



Sodium 



Zinc. 



Ammonium . 

 Potassium. . , 

 Cadmium . . , 



Weight (in grams) of 

 anhydrous salt in 

 100 c.c. of normal 

 solution. 



43 

 5-9 

 7 5 

 5-3 

 4-8 

 5 5 



13 -9 



13 8 

 14-6 



14- 9 



15- 9 



14 -4 



16- 5 

 18 3 



Thickness (in mm.) of 

 normal solution neces- 

 savy to produce the 

 same absorption as 

 20 mm. of water. 



18-1 

 18 

 17 8 

 15-1 

 13 4 

 11-2 

 9-0 

 8 3 

 8-2 

 8'2 

 7'2 



5-4 

 5 -3 

 2-6 



3 6 

 3-4 

 3 1 

 2-9 

 2-9 

 2-8 

 1-9 



