208 



Scientific Proceedings, Royal Dublin Society. 



group from A 2329 to X 2306 is peculiar, though many of them are very ftrong 

 lines in the spark spectrum of the metal, they do not show at all with the 

 vacuum tube spectrum of the metal unless the condenser is used. Some of 

 them, however, show with the chloride, both with and without the condenser. 



Prinicpal Lines of Cadmium, 



Zinc. 



Zinc and its chloride give a very brilliant luminescence when heated in 

 the quartz vacuum tube, and the introduction of the condenser makes very 

 little difference, and does not develop the spectrum of chlorine at the 



* Seen with the chloride but not with the metal. 

 ■^ Seen with the metal but not with the chloride. 



