YET A YEAR LATER, IOI 



The portion of the corona's substance which is thus self- 

 luminous is gaseous. It may well be, however, that 

 there is also a self-luminous portion in the solid or liquid 

 condition probably in a state of fine division. And it 

 has been rendered all but certain that a considerable 

 portion of the corona's light is simply sunlight reflected 

 from solid or liquid matter in the corona. For while it 

 is perhaps doubtful whether the solid or liquid matter is 

 self-luminous through intensity of heat, no question re- 

 maimS" as to the actual existence of such matter. Lastly, 

 it seems highly probable that a portion of the coronal 

 light has an electrical origin,like the light of our auroras. 

 Astronomers hope to obtain, during the eclipse of 

 December 1871, more satisfactory information than they 

 have at present respecting the actual extension of the 

 corona, as well as of the various portions of which it 

 consists. The observers will have to discriminate 

 between the light due to atmospheric illumination, 

 and those fainter and more delicate portions of the real 

 corona which have as yet not been traced to their actual 

 limits (if they have any). It is hoped, in particular, 

 that photographs taken at the extreme stations those 

 in India and Northern Australia will so confirm the 

 evidence first obtained from Mr. Brothers's photographs 

 as to convince the most sceptical that the corona is not 

 a mere atmospheric phenomenon. It may well be that 

 spectroscopists and polariscopists will obtain some new 

 information respecting the structure of the corona; 

 but to effect this they will have to overcome great 

 difficulties, owing to the way in which the light from 



