52 METEOEOLOGICAL 



phorescent properties : " It is not improbable/' 

 says Humboldt, "that the Moon, Jupiter, and 

 comets shine with an independent light besides 

 the reflected, solar light, visible through the po- 

 lariscope." 



We cannot do better than quote the following 

 passage also, by the same author : 



"Without speaking of the problematical, but 

 yet ordinary mode in which the sky is illuminated 

 when a low cloud may be seen to shine with an 

 uninterrupted flickering light for many minutes 

 together [see further on] , we still meet with other 

 instances of terrestrial development of light in our 

 atmosphere. In this category we may reckon the 

 celebrated luminous mists seen in 1783 and 1831 ; 

 the steady luminous appearance exhibited without 

 any flickering in great clouds observed by Kozier 

 and Beccaria ; and, lastly, as Arago well remarks, 

 the faint diffused light which guides the steps of the 

 traveller in cloudy, starless and moonless nights, 

 in autumn and winter, even when there is no snow 

 on the ground." 



Indeed, any attentive observer of Nature may 

 assure himself that in the darkest nights of winter, 

 at the hour of midnight, when the influence of 

 solar light is altogether withdrawn from the at- 

 mosphere, and in the absence of moonlight, a 

 suflicient quantity of light is always diffused to 

 render objects around us faintly visible, and to 



