24 SMITHSONIAN MISCEI.I.ANEOUS COLLECTIONS VOL. 8l 



And he later continues, " The facts hitherto reviewed may next 

 be considered in their bearing upon atmospheric questions. One 

 such question is, Are the layers affected by the two kinds of solar 

 emissions the same or dift'erent, and if diff'erent, what is their 

 relative situation ? 



" Even, a priori, it would be expected that two such different 

 emissions as corpuscles and ether waves will have different powers 

 of penetration into the atmosphere, though it would not be possible, 

 on such grounds alone, to decide whether the ' absorbing ' layers were 

 wholly distinct or not. The magnetic phenomena, however, give a 

 fairly clear indication that they are practically distinct without over- 

 lapping * * *," and he reaches the conclusion " that the magnetic 

 disturbance layer is situated at a higher level than the diurnal variation 

 layer." He infers from this that the magnetic disturbance layer (due 

 to ions from the sun) is situated between 90 and 120 km. and the 

 diurnal variation layer (due to ultra-violet light), between 10 and 

 90 km. 



Dr. Chapman has added a note dated July, 1919: "In a paper 

 read (on May 22, 1919) before the Institution of Electrical Engi- 

 neers, and shortly to be published, I have suggested that the ultra- 

 violet radiation * * * may be some type of gamma-radiation, and 

 that the corpuscles are (as Vegard has urged) alpha-particles. If both 

 these processes originate from radio-active processes on the sun, the 

 gamma-rays would be exj^ected to penetrate more deeply into our 

 atmosphere than the alpha-particles." All of which falls in with the 

 observations and suggestions of the present paper. 



Lord Rayleigh ' has recently published observations which relate 

 to a phenomenon possibly allied to that of ozone. These observations 

 are measurements of the intensity of the auroral green line in the 

 light of the night sky together with similar measurements of the 

 intensity in the spectrum of the night sky on each side of this line. 

 McLennan ' has shown that this green line owes its existence to a 

 metastable state of the oxygen atom. Whereas the green line is always 

 present in the light of the night sky, the negative bands of nitrogen 



' Proc. Roy. Soc. ii9A, u. 1928. 

 -Nature, 122, 38, 1928. 



