Brush Discharge in Weak Acids and Solutions. 815 



metal is gradually diminished. An increase in the quantity 

 of metal diminishes its relative intensity to the rest of the 

 spectrum. 



Sodium Salts. 

 The lines which appear and are due to sodium are : — 



•incipa] Series. 



1st Sub-series. 



2nd Sub-s< 



5893 



5685 



6163 



3303 



4981 



5152 



2853 



4667 



4755 





4492 



4544 





4392? 





The most brilliant line in the spectrum is the D doublet 

 (unresolved). No variation in relative intensity of the lines 

 has been detected save in one or two instances, where lines 

 of the 1st Sub-series have appeared close to the point, while 

 the D line has been weakest close to the point. 



Potassium Salts. 



The lines which occur and are due to potassium are : — 



Principal Series. 

 4045 

 3447 



The line \ = 4045 is very strong, while the line X = 3447 

 is very faint. These are the only lines in the spectrum 

 which appear. The following lines, with intensity in 

 brackets, appear at the negative point in all solutions of 

 potassium salts, and in no other solutions. I have been 

 unable to identify them : — 



3814 (10) 

 3798 (5) 

 3780 (1) 



Copper Nitrate. 



The lines due to copper are : — 



2442 (2\ 2619 (5), 3247 (10), 3274 (10), 

 4023 (1), 4063 (3), 4275 (1), 4651 (1), 

 5106 (2), 5153 (1), 5218 (3). 



The same spectrum appears in each brush when a copper 

 point is used instead of platinum. 



