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LIII. Ionization in the Solar Chromosphere. By Megh Nad 

 Saha, D.Sc, Lecturer on Physics and Applied Mathematics, 

 Calcutta University *. 



IT has been known for a long time that the high-level 

 chromosphere is generally distinguished by those lines 

 which are relatively more strengthened in the spark than in 

 the arc, and which Lockyer originally styled as enhanced 

 lines. The following list taken from Mitchell's f list of 

 chromospheric lines, along with the respective intensities 

 of the line in the arc and the spark, illustrates the case : — 



Table I.J 



Wave-length Chromospheric 



of the level reached Intensity. 



Element line in A.TJ.'s. in Kms. Arc. Spark. 



Calcium 3968 (H) ] 1400Q f 300 500 L 



3933(E) J I 500 1000 L 



Strontium 4216 \ 6000 500 500 L 



4078 J 6000 1000 1000 L 



Barium 4994 j 750 500 1000 L 



4554 J 1200 1000 1000 L 



Scandium 4247 6000 50 1000 L 



Titanium 3685"4 6000 8 100 



3741-8 1500 3 10 



3759 6000 10 20 L 



3761 6000 6 10 L 



3900 1600 5 50 L 



3914 2000 5 20 L 



4290 1300 2 10 L 



4294 1200 3 8L 



4300 1200 3 8L 



4395 2500 10 10 L 



4444 1600 4 15 L 



4468 1500 4 15 L 



4501 1600 4 15 L 



4563 1200 3 10 L 



4572 1200 5 20 L 



This table makes it quite clear that generally only those 

 lines occur in the highest levels which are relatively more 

 strengthened in the spark discharge spectrum. We can add 

 to the above table a list of the high-level iron and other 

 lines, but the conclusion would be the same. 



* Communicated by the Author. 



t Mitchell, ' The Astrophysical Journal,' vol. xxxviii# p. 424. 



X L denotes " enhanced " according to Lockyer. 



