3G BRIGHT CLOUDS ON A DARK NIGHT SKY. 



This latter was the hest Auroral manifestation I have seen this season. Many others I believe 

 have been noted in Sweden and Norway ; but those countries seem to be situated over one of the 

 Earth's invisible quabi volcanoes, or rather perhaps " maelstroms " of Aurorae ; so that as Professor 

 Angstrom noted many years ago, and Professor Lemstrom more recently, there is sometimes an Auroral 

 phosphorescence there on everything about them, air, earth, ice, and water. 



Such phosphorescence, however, as Professor Lemstrom has well remarked, is recognised by its 

 giving to the spectroscope the well-known Citron Aurora line, whose place is close, according to my 

 observations, to 45 550 W.N. Place. 



But other kinds of phosphorescence, so far as I have observed them, give only a band of continuous 

 spectrum in the green and glaucous regions, necessarily more refrangible than the Aurora line ; or 



Stick phosphorus in a chamber, has the maximum brightness of its 



broad, faint, band at . . . . . 49 000 W.N. PI. 



Animal phosphorescence at sea, has the similar centre at 



Carbo-hydrogen blue flame, when too faint to show its individual 

 lines, has its chief brightness near .... 



The Zodiacal light has the same, at or near 



Twilight has the same, at or about .... 



While Moon light, as above, has it at or near 



The last three therefore can hardly fail to be of one and the same Solar origination ; but the two 

 first are quite different from them ; and still more different are they from the chief Auroral line, both 

 in appearance and spectrum place; while the third suits our faintly bright night clouds of April 8, 

 1882, with' a broad slit perfectly. 



49 000 W.N. 



50 300 



49 200 



48 150 



48 150 



48 200 





