Absorption Spectrum of Zinc Vapour. 



361 



however, the band widened symmetrically, and with very 

 strong heating with a Meeker burner itcould easily be made 

 to cover a range of from one to two hundred Angstrom units. 

 No trace of any other absorption was found either above 

 A.2139'33 or in the region of the spectrum below this line 

 down as far as X1840. 



From the work of Wood *, Stark f, and others it is known 

 that the light corresponding to the lines \2536'72 and 

 X1849'6 is readily and easily absorbed by mercury vapour. 

 Wood and Guthrie % have also found that with cadmium 

 vapour there is strong absorption at \2288*78. With 

 cadmium vapour of high density these investigators have 

 found, too, that it is possible to obtain a narrow absorption 

 band at \3260*17 in addition to the one at \2288'79. From 

 the summary of wave-lengths given in Table I., which are 

 taken from Paschen's paper, it will be seen that all of these 



Table I. 



Single line series... n — l'b, S — m, P. 



m. 



Mercury Cadmium 

 (X). " (X). 



Zinc 

 (X). 



o 



18496 228879 



1402-71 1069-3 



1268*9 1526-73 



12506 146935 

 etc. etc. 



2139-33 



1589 64 



1457-04 



1376-97 

 etc. 



3 



4 



5 





Combination series... // = 2, p 2 — m, S. 



m. 



Mercury Cadmium 

 (X). " (X). 



Zinc 



(X). 



1-5 



2536-72 



4078 05 



2837-07 



2564-14 

 etc. 



3200-17 

 441323 



3082-8 



2757-1 

 etc. 



3075-99 



4294-0 



2981-8 



20064 

 etc. 



2-5 



35 



4-5 





* Wood, Astrophys. Jl. 1907, vol. xxvi. p. 41. 

 t Stark, Ann. der Phys. 1913, vol. xlii. p. 239. 

 X Wood and Guthrie, lac. cit. 



