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POPULAR SCIENCE MONTHLY. 



the evening of September 2, however, there was an exhibit which 

 could not be mistaken, I give it as written down at the time. 



"Low down on the southern sky there stands a faint arc of light, 

 and under it there is a distinct segment, darker than the sky above. 

 This segment has been noticed in several previous auroras, but it was 



Successive Displays op^ an Avstkai, Aukoka (in the Evening of September 2, 1898. 



not before so clearly defined. On board there is considerable difference 

 of opinion about this segment. Some have previously doubted its 

 existence, but to-night it is indisputable. I have taken the ground 

 that it is produced by the haze of ice crystals which always rests over 

 the ice, and I believe that its darkness depends upon the amount of 

 humidity or the thickness of the suspended icy haze. The stars shine 



