20 LIGHT SCIENCE FOR LEISURE HOURS. 



manner in which the light is emitted is also the same 

 in each case. We know certainly that the auroral 

 light is excited by the solar action. We know cer- 

 tainly that it is associated with the earth's magnetism. 

 The opinion, then, which we should form of the source 

 to which the other lights are due is tolerably obvious. 

 So long as electricity was merely used as a convenient 

 way of accounting for any perplexing phenomenon, it 

 was impossible to accept explanations of cosmical pecu- 

 liarities as due to electrical action. But when once we 

 have reason as in the case of the aurora we undoubt- 

 edly have to associate electricity with any particular 

 form of luminosity, we seem clearly justified in extend- 

 ing the explanation to the same form of luminosity 

 wherever it may appear. 



I believe that the key to the whole series of pheno- 

 mena dealt with above lies in the existence of myriads 

 of meteoric bodies travelling separately or in systems 

 around the sun. They are consumed in thousands 

 daily by our own atmosphere; they probably pour in 

 countless millions upon the solar atmosphere; and 

 from what we know of their numbers in our own neigh- 

 bourhood, and of the probability of their being infi- 

 nitely more numerous in the neighbourhood of the sun, 

 we have excellent reasons for believing that to them 

 principally is due the appearance of the zodiacal light 

 and the solar corona. 



(From FraseSs Magazine, February 1870.) 



