xxvi.] IRON AND NICKEL. 375 



The total number of iron lines in the first case is 96. Of those 

 96 lines only 38, or less than half, are found in the spots and 

 flames. When we go into the lower regions of the solar atmo- 

 sphere, we leave in fact more than half of the iron lines on one 

 side. Of these 96 lines 15 are found by other observers as well 

 as myself to be common to two or more substances. Now 

 comes the question, what is the behaviour of these common 

 lines with reference to spots and storms ? The table shows that 

 among the lines seen in spots and storms fourteen of these basic 

 lines are seen. It must be remembered that our records only 

 give us day by day the results of the 12 most widened lines, 

 and not of all the lines widened. In the next region the number 

 of iron lines is somewhat less 67 ; 41 of these, or more than 

 half, are picked out by spots and storms; 17 are basic. Of the 

 17 basic ones 15 are seen in the spots and storms, and only 

 2 are lines that are not seen. 



Next we will turn to another substance, nickel, and there we 

 see very much the same kind of thing at work. In nickel for 

 the region F to b we have 20 lines recorded by Thai en. 



Nickel. 



Total number of lines 20 



Number in spots and prominences . . v ;- . . . 3 



Basic lines . . 5 



seen in spots and prominences ... 3 



not seen ... 2 



> 



Of these -20, 17 are dropped, abolished; when we come to 

 observe the bright lines and the widened lines of nickel in 

 the spots and storms the 20 comes down to 3. Among the 20 

 lines 5 are found to be common to two substances. Of these 3 

 are seen in the spots or flames, that is to say, every line of 

 nickel seen in a spot or flame is common to two substances . 



