Manchester Memoirs, Vol, Ix. (1916), No. 10. 



X. Quantitative Absorption Spectra. Part II. A New 

 Ultraviolet Photometer. 



By Frederick Russell Lankshear, 

 B.A. (N.Z.), M.Sc. (Vict). 



(Read December ijt/i, 1Q14. Received for publication March gth, 191 5.) 



In a previous communication (October, 1914) certain 

 quantitative methods of examining absorption spectra 

 were described and it was mentioned that an instrument 

 was being made with a view to overcoming difficulties 

 due to the intermittent nature of the light received upon 

 the photographic plate. The present communication is 

 a brief description of the instrument made by Messrs. 

 Bellingham and Stanley. 



Optical System. Fig. 1 shows diagrammatically the 

 optical system used. 



°A 



s 



{7? 



m 



£] 



& 



Fig. 1. 



All the optical work is of quartz. Light from the 

 spark source 5 falls on the condenser A. This beam can 



August 22nd, 1916. 



