of Rubidium by the Spectroscope. 



397 



Standard. 

 Rubidium in a 

 coil-full (gV cm 3 ). 



0-00066 Dior 



Test solution. 



Rubidium in a 



coil-full with -, a „- 



of its weight of 



sodium. 



0-00066 mg. 

 0-00048 " 

 0-00046 " 

 0-00044 " 



Line of test 

 compared with 

 standard. 



Brighter. 

 Brighter. 

 Brighter. 

 Equally bright. 



It is plain that at the maximum degree of brilliance the 

 sodium is responsible for an increase of fifty per cent in the 

 brightness of the lines. 



The details of similar experiments in which potassium 

 chloride was introduced into the flame with the pure rubidium 

 chloride are given in the accompanying tabular statement. 



Standarc 





Test solution. 



Comparison of 



Comparison of 



Rubidium in a 



Potassium 



n 



lines of test 



lines of test 



coil- full (- s J - - 



cm 3 ). 



a coil-full 





taken by pairs. 



with standard. 



0-00066 



mg. - 



0-00020 

 0-00040 



rag. 



cc 



Slightly fainter. ) Briffhter 

 Slightly brighter, f nngntei. 



u 

 1 



« 



0-00020 

 0-00340 



u 

 a 



Fainter. ) 

 Brighter. ) 



Brighter. 



ct 



a 



0-00040 

 0-00066 



" f 



Equally bright 



Brighter. 



it 



I 



a 



0-00040 

 0-00340 





Brighter. ) 

 Fainter. \ 



Brighter. 



0-00066 



mg. - 



0-00066 

 0-00132 



" } 



Equally bright 



Brighter. 



a 



a . 



0-00066 

 0-00246 



a 

 a 



Brighter. ) 

 Fainter, j 



Brighter. 



a 



u 



0-00066 

 0-00660 





Brighter. | 

 Fainter. | 



Brighter. 



a 



1 



i 



a 



0-00066 

 0-01320 



a ■ 



Brighter. ) 

 Fainter. [ 



Brighter. 



a 



a 



' 0-00066 



a 



Brighter. 



Brighter. 







0-02000 



a 



Fainter. 



Equally bright 



a 



a 



' 0-00066 



a 



Brighter. 



Brighter. 







0-02660 



a 



Fainter. 



Equally bright 



a 



a 



0-00066 



a 



Brighter. 



Brighter. 







0-03340 



a 



Fainter. 



Equally bright 



a 



a 



000066 



a 



Brighter. 



Brighter. 



^ 





0-03340 



a 



Invisible. 



Invisible. 



From these results it appears that the presence of potassium 

 produces an effect upon the rubidium lines similar to that of 

 sodium ; and, furthermore, the addition of 0'0004 mg. of 

 potassium in the form of chloride to 0'00066 mg. of rubidium 

 also in the form of chloride brings out the maximum bright- 

 ness which is not materially changed by further addition of 



