214 



Scientific Proceedings, Royal Dublin Society. 



beautiful blue bands were seen to develop whenever there was an excessive 

 quantity of vapour in the tube. The bands can be seen on the plate from 

 about wave-length 4700 to 4100. When the condenser was introduced, 

 there was a forked spark of a blue colour, with red border. The bands were 

 greatly reduced, and the chlorine spectrum came out on the plate. 



