November 1 6th, i p 75.] Proceedings. xix 



in Zoology in the Victoria University of Manchester, and of 

 6p, Mauldeth Road, Withington, Manchester, was elected an 

 ordinary member of the Society. 



Ordinary Meeting, November 16th, 19 15. 



The President, Professor Sydney J. Hickson, M.A., D.Sc, 

 F.R.S., in the Chair. 



Dr. G. A. Hemsalech, F.R.A.S., read a paper entitled, 

 " On the Spectra emitted by metal vapours in the 

 explosion region of the air - coal-gas flame." 



After a review of the work done on Bunsen flame spectra by 

 M. de Watteville and on the different flame spectra of calcium 

 and iron by Hemsalech and de Watteville, the author described 

 a simple and convenient burner by means of which the various 

 flame phenomena can be readily subjected to spectroscopic 

 observation and experiment. Photographs were shown to illus- 

 trate the changes in the Swan spectrum emitted by the explosion 

 region of flames on passing from rich to very weak gas mixtures. 

 For very weak mixtures the ordinary Swan spectrum disappears 

 and another band spectrum develops. 



Some experiments were then shown to demonstrate the action 

 of electric fields on the flames of weak gas mixtures charged 

 with sodium vapour. The great sensitiveness of such flames 

 in a longitudinal field was illustrated in several ways, and, in 

 particular, it was shown that when the gas mixture had become 

 so weak that in the absence of the electric field it would no 

 longer ignite, it would do so immediately on the field being 

 restored. 



