PHOSPHORESCENCE. 51 



Borealis, certain portions of the heavens which 

 were not illuminated, lit up and continued lumi- 

 nous whenever a shooting star passed over them. 



M. Colla, formerly director of the Observatory 

 of Parma, has often observed, since 1825, a sin- 

 gular light in the northern sky, like a zone of 10 

 or 12 degrees, parallel to the horizon, often of a 

 yellow colour, and most intense in the direction of 

 the magnetic meridian. He considers it to be 

 " the permanent element of the Aurora Borealis." 



That portion of the planet Yenus which is not 

 illuminated by the sun often shines with a phos- 

 phorescent light of its own. 



Towards the latter end of June, 1861, the 

 earth passed through a region of the heavens, 

 then occupied by a portion of the great comet of 

 that year. On this occasion Mr. Hind, Mr. Lowe, 

 and others, observed a peculiar phosphoric glare 

 in the atmosphere. It was remarked by many 

 persons as something unusual. 



That portion of the moon which is not il- 

 luminated by the solar rays shines with a grey 

 light of its own, called by the French lumiere 

 cendree. This is generally attributed to the light 

 thrown upon our satellite by the illuminated por- 

 tions of the earth ; but it may be that the moon 

 possesses phosphorescent qualities like other ce- 

 lestial bodies. 



Doubtless other planets possess similar phos- 



