1092 



Mr. D. Coster on the Spectra of X-rays 



Fig. 5 shows cci and (3 X with their satellites for Zr, taken at 

 two different heights of the plate. On the plates of the 

 elements Mo-Rb taken with a gypsum crystal, c/ z could not 



Fig. 4. 



AgLSi and In L/3 L with their satellites (calcite ciwstal). 



Fig. 5. 



Zr La x and L/3 L with their satellites (gypsum crystal). 



be separated from «/. This gives a somewhat asymmetrical 

 form to this line. a 2 and /3/, which could be detected easily 

 with the eye, could not be separated from a 1 and /3iwith the 

 photometer. Fig. 3 (PI. XXIII.) gives a reproduction of 

 the ay and /3i-lines of Rb. 



The wave-lengths and frequencies of the a x - and fii- 

 satellites are given in Tables VII., VIII., and IX. The wave- 

 lengths of a 3 for Mo-Rb are probably too great, since this line 



