Radioactivity of Lead and other Metals. 



767 



calculate Ii p , I Zs , and I as , and so deduce a relation between 

 the ionizations produced in a given lead cylinder by the 

 gamma ray r s which enter it and by the secondary rays 

 excited in the walls of the vessel by these penetrating rays. 



The averages of a great many measurements made in 

 this way with the cylinders Nos. 1, 2, and 3 are given in 



Table IV. 



Cylinder 



No. 



Natural ioni- 

 zation (Arbi- 

 trary Scale). 



Reading "«." 



Natural ioni- 

 zation (Arbi- 

 trary Scale). 



Reading " b." 



Combined ioni- 

 zations in. un- 

 lined lead cylin- 

 der (Arbitrary 



Scale). 

 Reading " c." 



Combined ioniza- 

 tions in aluminium- 

 lined lead cylinder 



(Arbitrary Scale). 



Reading " d." 



1 



2 



3 



7*7 

 5394 

 12 



4-02 

 448 

 4-67 



97-75 

 142-44 

 113 



53'52 

 48-87 

 57-97 



Table IV.; and in Table V. the numbers corresponding to 

 the reduced values of these observations are recorded. 



Table V. 



Column 1. 



Column 2. 



Column 3. 



Column 4. 



Column 5. 



Column 6. 



Column 7. 





ce^d a c, 



^t3 3 oo O 







A ° S ^ 



_ 





3 *'« + 



5 = ' rt *>£ 







5 2.2® 



■73 C^ 





3 M M 



s3 _. £ m 



S O IB ?". 







5 © P .2 



-2 3 



Cylinder 

 "No. 



tion clue to 

 from radi 

 dary rays e 

 y these rays, 

 trary Scale.) 



tion due to 

 from radi 

 dary rays e 

 nium by tb 

 las. (Arbitra 



Ratio 

 (calculated) 



Ratio 

 las 



(calculated) 



"■§.9 £^ 

 ■si? ■§■ 



o fee* -1 



Or2 g g 



O r2 



U ^3 



o 



h-i C 

 O 





niza 



ays 



econ 



sad! 



Arbi 



•a £§.§.§■ 







'a •£ 2 * 



2 o 





I— \ ' •— ' v — ' 



o ^ co se i— i 

 M 







£- Pi* 



>* 



1 



90-05 



49/5 



1-74 



•49 



33-05 



f^-x3' 



\84-64 X dt 



39-0 

 j-05) =390 



2 



88-50 



44-39 



2-31 



•66 



26-7 



32-0 



3 



101-00 



53-3 



1-95 



•56 



•57 



34-2 



380 









Mean 



... 2-00 



31-32 



363 



Applying equations (i.), (ii.), and (iii.) to the measurements 

 with cylinder No. 1, as an example of the manner in which 



