148 LIVING LIGHTS. 



air about Naples, which was not particularly noticeable ; 

 but as night came on, it emitted a pale though distinct phos- 

 phorescent light. An English gentleman sailing near Torre 

 del Greco noticed that where the dust collected upon his 

 hat it was luminous, and no little consternation was caused 

 among the superstitious sailors by the occurrence. 



Luminous dust-showers have been noticed in several local- 

 ities ; and the peculiar glows that were seen in this country 

 a few years ago were accredited by many to them, the sup- 

 position being that dust, perhaps from volcanic eruptions, 

 was floating about in the upper strata of the atmosphere. 

 Many other explanations were given, and the literature upon 

 the subject is extremely voluminous and interesting. 



The amount of material floating about in the upper regions 

 of the air is perhaps little realized by my young readers, 

 and some reference to the phenomenon may be of interest. 



Professor Nordenskjold has for many years been a close 

 observer of dust of all kinds that has fallen upon the 

 earth in rain or snow ; and it was his good fortune, during 

 the expedition of the " Vega," to prove beyond a doubt the 

 presence of cosmic dust. For many years we have been 

 assured by astronomers that the earth was being bombarded, 

 as it were, continually, by innumerable meteors. The 

 moment they enter our domain, we observe the spectacle of 

 their ignition. In a moment they are reduced to ashes, and 

 the fine impalpable dust drops slowly, an invisible shower, 

 upon the earth. When such showers are intensified, it is 

 not impossible that some outward and visible phenomena 

 may be the result. 



In the search for this cosmic dust, the far North, where the 

 surface is covered by an almost continuous coating of snow 



