THE AURORA. 19 



eclipse, exhibited the same bright lines as the aurora. 

 The fact that auroral lines are mentioned will at once 

 be noticed ; but it is to be remarked that the two faint 

 lines which have been lately seen in the auroral spec- 

 trum correspond to but a very small portion of the 

 light we receive from the northern streamers. In the 

 spectrum of the corona the same three lines appear, 

 but their relative brightness is different. The brightest 

 line of the auroral spectrum is faint in the spectrum of 

 the corona, while the latter exhibits a bright line where 

 the former has a faint one. 



News has also been received that a comparison of 

 the photographs of the eclipse proves the corona, or 

 at any rate its brightest part, to belong to the sun. 



Lastly, it has been found that the peculiar phospho- 

 rescent light sometimes visible all over the sky at night 

 gives the same spectrum (very faint, of course) as the 

 aurora and the zodiacal light. 



It is impossible not to recognise the fact that these 

 discoveries point to relations of the utmost importance. 

 The teachings of the spectroscope are too certain to be 

 mistaken. When it shows us such and such lines 

 bright or dark, we may conclude, without fear of being 

 misled, that such and such substances are emitting or 

 absorbing light. What we learn certainly, therefore, 

 from the facts above stated, is this, that substances of 

 the same sort emit the light of the aurora, of the zodia- 

 cal gleam, of the sun'& corona, and of the phosphor- 

 escence which illuminates at times the nocturnal skies. 

 We may conclude, but not so certainly, that the 



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