lO 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8/ 



It is evident from these curves that the intensity in the 2,536 A. 

 region as measured hy the thermocouple is largely due to the resonance 



I '^ l,n,l,„^:„l„„ln„l,„^^ l± ^ I, y,UjiPl 1^? I ^ H IP 



M I III I II II I II I III I I I I II I II I III 



"I T 



SHARP SINGLETS 



COMBINATIONS 



Fig. 2. — Absolute intensities 250 mm fruni a 20 mm mid-section of the " low 



intensity " arc. 



line in the low-intensity arc, v^hile A 2.534.8 and the background are 

 practically all that affect the thermocouple in the high-intensity arc. 



