198 



Mr. J. Norman Lockyer. 



provisional adhesion, as a working hypothesis to be constantly tested 

 by reference to observed phenomena." 



I am anxious to refer here also to the opinion expressed by my 

 friend and colleague, Professor Roberts- Austen, whose researches 

 have mostly been carried on at high temperatures : — 



il Mr. Lockyer has, however, since done far more : he has shown 

 that the intense heat of the sun carries the process of molecular 

 simplification much farther ; and, if we compare the complicated 

 spectra of the vapours of metals produced by the highest tempera- 

 tures available here with the very simple spectra of the same metals 

 as they exist in the hottest part of the sun's atmosphere, it is diffi- 

 cult to resist the conclusion that the atom of the chemist has itself 

 been changed. My own belief is that these ' atoms ' are changed, 

 and that iron, as it exists in the sun, is not the vapour of iron as we 

 know it upon earth."* 



The Basic Lines. 



With regard to the basic line part of the inquiry, I think I shall 

 not be going too far in saying that it has been universally rejected, 

 and chiefly on the ground that some lines which appeared coincident 

 at the dispersion I employed appeared double with higher disper- 

 sions. I have pointed out in the ' Chemistry of the Sun ' (p. 377) that 

 this is not a sufficient answer, but I have left aside this branch of 

 the inquiry for some years in the hope that some chemist would 

 take up the question of spectroscopic impurities out of which it 

 grew. 



Bat it is evident that this basic line point of view, even though it 

 be considered a less direct attack on the problem than others, 

 assumes a much more important and definite position in the light of 

 the new work. I will not go into this question at length now, but 

 will content myself by asking whether one actual demonstration of 

 dissociation will not take a form very like that which the chemist 

 has taken to be a demonstration of the existence of impurities. 



§ 3. Discussion of the Bearing of the Stellar Researches on the 

 Hypothesis. 



Extension of the Field of Investigation. 



I now proceed to consider whether the views which I have found 

 necessary to enable me to group together harmoniously and con- 

 tinuously solar phenomena are weakened or strengthened by the 

 study of the new field of investigation opened out by the recent 

 stellar work. 



* 1 Roy Inst, Proc.,' vol. 13, p. 509. 1892. 



