376 THE CHEMISTKY OF THE SUN. [CHAP. 



Passing on to calcium we find the same result. 



Calcium. 



Y-b 6-5480 

 Total number of lines 2 . 7 



Number in spots and prominences 2 . 5 



Basic lines 2 . 4 



seen in spots and prominences. . . 2 .4 



not seen 0.0 



This is all the work of this nature which we need now 

 consider, but it is not all the work that has been done. In the 

 case of every part of the spectrum, in the case of every sub- 

 stance, the verdict is in the main the same. We have the fact, 

 that two things are observed exactly parallel to each other first 

 that some lines are common to two substances ; next that the 

 lines common to two substances are seen almost exclusively 

 alone, both in the sun-spots and in the prominences. So that 

 in addition to the fact that the hottest regions of the sun seem 

 to simplify the spectra of the substances enormously, we have 

 the further result that the simpler the spectrum becomes, the 

 more complex becomes the origin of the lines ; by which I mean 

 that in the ordinary solar spectrum there are a great many lines 

 due to iron, and to nothing else ; to calcium, and nothing else ; 

 and so on ; but the moment we come to the simpler spectrum 

 yielded to us in the spots or the flames, then we have no more 

 right to say that many lines belong to iron than that they belong 

 to titanium, cerium, nickel, and other substances with which 

 those lines have been observed to be coincident with the 

 dispersion employed. 



Some of the strongest objections which have been urged 

 against my views have arisen from the fact that the lines which 

 I called "basic" in 1878 have since been found, as I have shown, 

 not to be absolutely coincident, the majority of them being 

 close doubles. I know not whether the views I have put 

 forward above, and the facts I have stated, will be acknowledged 



