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Scientific Proceedings, Royal Dublin Society. 



tube provided with a quartz window. By this means we were able to 

 compare the solution and metallic spark spectra directly. We were not able 

 to procure a specimen of metallic caesium for comparison with the spectrum 

 of the chloride. 



A line at A 2478 occurs in the spectra of metallic lithium and rubidium, 

 but not in the spectra of the chlorides. We were not able to establish the 

 identity of this line, and have marked it with a query. 



Lithium. 



Solutions of lithium chloride were examined with gold electrodes, and the 

 persistency of the lines recorded. The lithium line at A 4602'5 appeared, 

 however, to be masked by coincidence with Au A 4601 - 6, and it was thought 

 advisable to repeat the experiments with copper electrodes. Examined in 

 this way the line was well shown, and was easily followed through the 

 dilutions. 



The most persistent lines are at AA 6708-2 and 4602-5. 



Quantitative, Spectrum of Lithium Chloride. 



