the Wave-Length of the Soft y Rays from Radium. B, 861 



d = 2*814 Xl0~ 8 cm. being taken from MoseleVs paper. 

 The spectrum of the characteristic radiation from platinum, 

 suitably reduced by division by a constant factor, is added 

 for comparison : this will be referred to again later (p. 864). 



Table I. 



1 



Radium B. 





.1 



Platinum. 



Soft 



y-ray spectrum. 





X-ray spectrum. 



i 



! Angle of reflexion 

 from rocksalt. 



Wave-length 

 (in cm.). 



Intensity. 



Angle of reflexion 



1-122 



8° 6' 



•793 XlO -8 



m. 





8° 16' 



•809 



m. 





8° 34' 



•838 



rn. 



8° 27' 



8° 43' 



•853 



m. 



8° 43' 



9° 23' 



•917 



f. 





9° 45' 



•953 



m. 





10° 3' 



•982 



s. 



10° 2' 



10° 18' 



1-006 



m. 



10° 13' 



10° 32' 



1-029 



m. 





10° 48' 



1055 



f. 





11° 0' 



1-074 



f. 





11° 17' 



1-100 



f. 





11° 42' 



1-141 



m. 





12° 3' 



1175 



s. 



12° 3' 



12° 16' 



1-196 



in. 





12 u 31' 



1-219 



f. 





13° 0' 



1-266 



f. 





13° 14' 



1-286 



f. 





13° 31' 



1-315 



f. 





13° 52' 



1-319 



in. 





14° 2' 



1-365 



m. 





Fier. 3. 



10 I i 



R ad iutti 



12. 



13 



'*h 



B 



^^^~t 



1r+ 



■2, l'3 



a t i n u ra 



tH 



IV 



In fig. 3 the spectrum is shown diagrammatically, and 



below it that of platinum, the scale being adjusted so as fco 



