CHAPTER XIV. 



DETAILS OF SOME OF THE DIFFICULTIES. 



1. The Spectrum of the Prominences. 



DURING the accumulation of the observations of the bright 

 chromospheric lines described in Chapter IX., many phenomena 

 difficult to understand presented themselves. 



The following is a list 1 of the lines the positions of which 

 were known at the end of 1869 : 



Kirchhoff's numbers. 



C 

 F 



Near G 



h 



Near D 



1989-5 

 2031-2 



1474 



1515-5 



1529-5 



Wave-lengths. 



6561-8 

 4860-6 

 4340-1 

 4101-2 

 5874-9 

 ( 5895-0 ) 

 { 5889-0 j 

 4933-4 

 4899-3 

 5183-0 

 5172-0 

 5168-3 

 5166-7 

 5315-9 

 5275-0 

 5263-9 



Element in the spectrum, of 



which corresponding lines 



had been recorded. 



Hydrogen. 



Sodium. 



Barium. 



> 

 Magnesium. 



Nickel. 



Magnesium, 



Iron. 



() 



Bright line. 



1 " Spectroscopic Observations of the Sun," No. V., Proc. Roy. Soc. vol. xvii. 

 pp. 74 and 118, July, 1869. 



