314 



Sir E. Rutherford on the 



of this unit. The original difference unit '4284 x 10 13 e y 

 when multiplied by three gives 1'285 xl0 13 £, which does 

 not differ from 1*25 x 10 13 e by more than the experimental 

 error. It will be seen in the table below that a number 

 of the lines, including some of the stronger lines, can be 

 expressed very closely as integral multiples of the unit 

 E = 1-285 xlO 13 *. 



The numbers of the lines refer to those given in the 

 previous paper by Rutherford and Robinson. 



Index 



number of 



line. 



Intensity. 



M45 

 K38 



32 

 G29 

 F26 



23 

 D20 



17 

 14 



11 



m. 



s. 

 m.f. 

 m.s. 



m. 



f. 



m. 



f. 



m. 



f. 



Velocity as 



a fraction 



of light. 



•750 



•868 



•917 



•946 



•952 



•959 



•9643 



•9687 



•9724 



•9754 



Observed 



energy 



-=-10 13 e. 



2-59 

 5-16 

 7-68 

 10-31 

 11-49 

 12-82 

 14-09 

 15-42 

 16-71 

 17-96 



Energy 

 •l-285xi0 13 e. 



2-015 



4-016 



5-98 



8-02 



8-94 



9-97 



10-96 



12-00 



1301 



13-97 



Integral 

 multiple. 



2 



4 



6 



8 



9 



10 



11 



12 



13 



14 



Of the twelve strong lines in the table marked with index 

 letters, six are seen to be expressed very nearly as integral 

 multiples of E : . In picking out possible other units, it 

 appears significant that another series of lines can be 

 expressed as a multiple of E 2 = '74x 10 13 e. This is seen in 

 the following table. 



Multiple ... 



2 4 6 8 



9 12 



14 



15 



16 

 11-84 



18 



19 



22 23 

 16-28 17-02 



Calculated 

 energy ■? 10 l3 e. 



1-48 1 2-96 4-44 5-92 



6-76 8-88 



10-36 



11-10 



13-32 



14-06 



Observed 

 energy -^-10 13 e. 



1-49 2-96 4-48 5'94 



6-74 8 91 



10-31 



m.s. 



11-07 

 f. 



11-86 

 y.f. 



13-28 



14-09 16-28 17-11 



Intensity ... 



f. m. m.f. m.s. 



m.f. m.f. 



m.s. 



m. f. f. 



Only two of these lines, viz. of energies 10'31 and 14'09, 

 are included in the first table. These lines may possibly be 

 close doubles. 



It has been pointed out in the paper of Rutherford and 

 Andrade that the strong y ray line reflected at 1° 40' is 



