Tables 603-505. 



RADIOACTIVITY. 



TABLE 603.— Stopping Powers of Varlons Sabstances for a Rays. 



395 



s, the stopping power of a substance for the a rays is approximately proportional to the square 



root of the atomic weight, w. 



Bragg, Philosophical Magazine, ii, p. 617, 1906. 



TABLE 504/— Absorption of j3 Rays by Various Substances. 



H, the coefficient of absorption for j8 rays is approximately proportional to the density, D, 



Table 506 for ix for Al. 



See 



For the above data the ;8 rays from Uranium were used. 

 Crowther, Philosophical Magazine, 12, p. 379, 1906. 



In determining the above values the rays were first passed through one cm. of lead. 

 Russell and Soddy, Philosophical Magazine, 21, p. 130, igii, 

 Smithsonian Tables. 



