Rays emitted by Substances exposed to 7 Rays. 631 



the sixth, seventh, and eighth columns of the table respec- 

 tively. Hydrogen is the only gas showing a serious deviation 

 from the additive law. If the elements given in the fifth 

 column could exist as monatomic gases, the atomic ioniza- 

 tions would give their ionization per c.c. It will be seen 

 that the atomic ionizations for the /3 and 7 rays are also 

 approximately the same. 



But i£ we compare the atomic ionizations with the values 

 of Mi and M 2 , we see that the values of M 1 and M 2 increase 

 more rapidly with increase of atomic weight than the atomic 

 ionizations. Let us examine these quantities more closelv. 

 beginning with the ionization in a gas. The ionization in a 

 gas consists of the primarily ejected electrons, and the ions 

 that these electrons produce by collision. Since the primary 

 electrons are ejected with a considerable velocity, the former 

 quantity is probably small in comparison with the latter. 

 The ionization per c.c. in a gas may therefore be expressed 

 in terms of two factors, which are respectively proportional 

 to the primary and secondary or collision ionization. This 

 product for any particular gas expressed in terms of that of 

 air must be the same for the /3 and 7 rays, according to the 

 experiments of the writer in Table III. The velocity of the 



Table III. 



gL. 



lonizatic 





per c.c 





r rays- 





1-00 



o 2 



116 



co 2 



1-58 



CHO ... 



1-7.3 



C 4 H 10 O... 



4'20 



C G H 



3-94 



C 5 H 12 ... 



4-53 



C o H 4 ... 



2-17 



Ko 



1-55 



c x, 



1-71 



CH,T 



5-37 



C 2 H,I ... 



Cv47 



CH^Cl ... 



493 



C 2 H 5 C1 ... 



319 



CC1 



6-33 



cs„ 



36G 



CH.Br ... 



3-81 



C H-Br ... 



4-58 



SO. 



2-27 



If Ho 



•898 



Ho 



•160 







per c.c. per c.c. 

 )3 rays. a rays. 



100 

 115 



1-59 

 1-74 

 4-40 

 430 

 4-85 

 2-14 

 153 

 1-94 

 3-43 

 4 00 

 4-08 

 312 

 5-28 

 2-99 

 2-75 



201 

 •99 

 •24 



Atom. 



1-00 

 1-17 

 1-60 

 169 

 4-39 

 3-95 

 4-55 

 212 

 1-55 

 1-86 

 5-11 

 5-90 

 4-94 

 324 

 6-28 

 3-62 

 373 

 4-41 

 2-25 

 •888 

 •165 



I 

 Ionization Ionization Ionization 



per atom, per atom, j per atom. 



y rays. /3 rays. \ a rays. 



H 



•18 



C 



•46 



N 



•45 



O 



•58 



s .. 



1-60 



CI 



1-44 



Br 



2-81 



I 



4-50 



•18 



•46 



•475 



•58 



1-60 



1-44 



2-67 



4-10 



•175 



•51 



•47 



•55 



1-24 



116 



1-72 



2-26 



