Kent. — Spectra of the Zinc Arc and Spark, 



Plate 2. 



88a 89b 89c 



I 

 I 

 i 



f 



48c 85a 



78c 



79e 



SOa 



I I 



I I 



I I 



65b 



6Sa 



94c 94cl 



94e 



96c 



96tl 96e 



Proc. Amer. Acad. Arts and Sciences. Vol. XLVIII. 



