528 Constitution of H and K Vines of Solar Spectrum. 



When the liquid terminals described above are saturated 

 with chemically pure chloride of calcium, with nitrate of 

 strontia, with nitric acid, the great H.H. lines and the line at 

 wave-length 4227 are greatly enhanced. This gives strong- 

 colour to the above hypothesis. There is evidently an electro- 

 chemistry of the air which has been opened by the discovery 

 of argon. 



The continuous spectrum observed with disruptive dis- 

 charges in gases occurs also when electrical discharges are 

 obtained in distilled water, and in certain other liquids. 

 Prof. TVilsing*, Prof. Halef, and Sir Norman Lockyer J have 

 discussed the reversed lines observed under this condition. 

 The phenomenon of continuous spectrum and of reversals is, 

 I believe, of the same nature as the phenomenon observed by 

 me in gases. The continuous spectrum is due to a sudden 

 compression of the medium under the powerful disruptive 

 electrical explosion, and the reversals are due to a polariza- 

 tion and not to a reversing layer. The reversed lines ob- 

 served by me increase in intensity toward the ultra-violet, 

 and also are strengthened by repeated exposures. This is 

 the case also with the reversed lines observed under water. 



The conclusions of my first paper in the Phil. Mag. July 

 1902 are therefore confirmed by further investigation. At 

 the basis of the great H.H. lines of the solar spectrum, there 

 are strong gaseous lines which I believe to be oxygen lines. 

 The reversed lines are not due to calcium but are due to 

 oxygen. 



The accompanying Plate (XIII.) shows the normal spectra 

 which illustrate this article. Fig. 1 represents the gaseous 

 lines which closely correspond with the great H.H. lines of the 

 solar spectrum. Pig. 2 represents the spectrum of calcium 

 in the neighbourhood of the H.H. lines. It is seen that 

 strong lines of calcium are conspicuously absent in fig. 1. 



Fig. 3 shows the gaseous lines obtained in a quartz tube 

 filled apparently with pure hydrogen. A strong group of 

 magnesium lines is added for comparison. These magnesium 

 lines are the strongest lines of that metal between wave- 

 length 3000 and 2000. 



Fig. I gives also the same comparison spectrum of mag- 

 nesium, and reversed lines of the gas contained in the quartz 

 tube. 



In fig. 3 there is no continuous spectrum. The argument 

 of incandescent walls to account for the continuous spectrum 

 in the case of the employment of glass Geissler tubes, would 



* Kavser, 1 C. 1 P. p. 228. 



f G. *E. Hale, Astrophvs. Joum. p. 15 (1902). 



X N. Lockyer, Proc. Roy. Soc. p. 70 (1902). 



