34 INORGANIC EVOLUTION. [CHAP. 



the old, it is desirable to refer briefly to some of the work undertaken 

 in relation to some of the first anomalies noted. 



One advantage of this method of treatment is that it shows that 

 the immense mass of facts now available supports all the conclusions 

 drawn from the meagre evidence available a quarter of a century ago. 



Some of the anomalies were as follows : they are given as specimens 

 of many. 



1. Inversion of intensity of lines seen under different circum- 

 stances. 



I showed in 1879 that there was no connection whatever between 

 the spectra of calcium, barium, iron and manganese and the chromo- 

 sphere spectrum beyond certain coincidences of wave-length. The 

 long lines seen in laboratory experiments are suppressed, and the 

 feeble lines exalted in the spectrum of the chromosphere. In the 

 Fraunhofer spectrum, the relative intensities of the lines are quite 

 different from those of coincident lines in the chromosphere. 



2. The simplification of the spectrum of a substance at the tem- 

 perature of the chromosphere. To take an example, in the visible 

 region of the spectrum, iron is represented by nearly a thousand 

 Fraunhofer lines ; in the chromosphere it has only two representatives. 



3. In sun spots we deal with one set of iron lines, in the chromo- 

 sphere with another. 



4. At the maximum sun-spot period the lines widened in spot 

 spectra are nearly all unknown ; at the minimum they are chiefly due 

 to iron and other familiar substances. 



5. The up-rush or down-rush of the so-called iron vapour in the 

 sun is not registered equally by all the iron lines, as it should be on 

 the non-dissociation hypothesis. Thus, as I first observed in 1880, 

 while motion is sometimes shown by the change of refrangibility of 

 some lines attributed to iron, other adjacent iron lines indicate a state 

 of absolute rest. 



Laboratory work without stint has been brought to bear, with a 

 view of attempting to explain the anomalies to which attention has 

 been directed. 



I only refer here to the work done on iron, magnesium and calcium, 

 to show that in those metals the anomalies were to a large extent due to 

 the lines now termed enhanced that is, the lines seem to considerably 

 change their intensities when the highest temperatures are employed. 



Iron. 



In the course of my early observations of the spectrum of the 

 chromosphere, I discovered on June 6, 1869, a bright line at 1474 on 



