[mclennan-young-ireton] absorption SPECTRA 13 



2. It is possible that the systems of narrow and diffuse absorp- 

 tions may correspond to the analogous series absorptions of thallium 

 and aluminium. 



(d) Tin 



1. Three absorption bands of tin were obtained but no identifica- 

 tion of series is yet possible. 



(e) Arsenic 



1. The flame spectrum of metallic arsenic has been found to 

 consist of five lines: A = 3266 A.U., A = 2860 A.U., A = 2780 A.U., 

 A = 2350 A.U. and A = 2288 A.U. together with four bands with heads 

 at A = 2634 -5 A.U., A = 2570 A.U., A = 2503 -5 A.U. and A = 2437 -3 A.U. 



2. The arc absorption spectrum has been found to consist of four 

 strong unilateral bands, the sharp edges of which were towards the 

 red and occurred at wavelengths A = 2634 -5 A.U., A = 2570-0 A.U., 

 A = 2503-5 A.U., A = 2437-31 A.U. 



3. Contrary to expectation no single line absorption or emission 

 was found which could possibly be supposed to correspond to the line 

 A = 2620 A.U. predicted by Foote and others.^ 



Admiralty Physical Laboratory, 

 South Kensington. 



14th April, 1919. 



' Foote, Rognley and Mohler — loc. cit. 



