t^OLLOK — the Vacuum Tuhe Spectra of some Metallic Vajwurs. 213 



Bismuth. 

 I did not succeed in getting a good vacuum tube spectrum of metallic 

 bismuth, the spectrum being due almost entirely to a trace of arsenic present 

 in the metal, though one or two bismuth lines were seen. With the chloride 

 there was a brilliant luminescence of a deep blue colour, and this was easily 

 maintained by the use of an ordinary Bunsen. Unfortunately a little 

 nitrogen found its way into the tube, so the nitrogen bands are seen as well 

 as the lines of bismuth. The introduction of a condenser did not make any 

 notable change in the spectrum, and the chlorine lines did not develop on the 

 plate. 



Principal Lines of Bismuth. 



COPPEK. 



Metallic copper was not tried, as it was not thought likely to be suflS- 

 ciently volatile to yield a spectrum ; but the chloride gave a brilliant blue 

 luminescence in the tube, and when watched with a hand spectroscope 



