314 THE CHEMISTRY OF THE SUN. [CHAP. 



A, B, C, that we may get A and B without C, A and C without 



B, B and C without A, and so on. 



One was struck with the marvellous individuality, so to 

 speak, of each of the lines. They did not go in battalions, or 

 companies, or corporal's guards, but in single unities. Each in 

 turn is seen without the other. We get as. much inversion of 

 lines in the case of one element as we could do between the 

 lines of different elements ; by which I mean that the lines of 

 nickel, say, are just as much varied in different spots as the 

 lines of iron, nickel or calcium would be in spots in which the 

 proportions of these substances very greatly varied. 



5. Very few lines, indeed, are strongly affected at the same 

 time in the same spot. A great many lines of the same sub- 

 stance may be affected, of course, besides the twelve recorded 

 as most widened on each day ; but a small number relatively 

 altogether are affected in this manner. 



6. Many of the lines seen in the spots are lines seen at low 

 temperatures (some of them in the oxyhydrogen flame), and none 

 of them are those brightened or intensified when we pass from 

 the temperature of the electric arc to that of the electric spark. 



7-. Certain lines of a substance have indicated rest, while other 

 adjacent lines seen in the spectrum of the same substance in 

 the same field of view have shown change of wave-length. 



8. A large number of the lines seen in spots are common to 

 two or more substances w r ith the dispersion employed. 



9. The lines of iron, cobalt, chromium, manganese, titanium, 

 calcium, and nickel seen in the spectra of spots are usually coin- 

 cident with lines in the spectra of other metals, with the dis- 

 persion employed ; whilst the lines of tungsten, copper, and zinc 

 seen in spots are not coincident with lines in other spectra. 



10. The lines of iron, manganese, zinc, and titanium most 

 frequently seen in spots are different from those most frequently 

 seen in flames, whilst in cobalt, chromium, and calcium the 

 lines seen in spots are the same as those seen in flames. 



