THE SOL All ECLIPSE OF 1871. 149 



the fact that the space included within the outer limits of the 

 visible corona is at least twenty times as great as the bulk of 

 the sun itself, that above twenty-five millions of our worlds 

 would be required to fill it. 



Jannsen says: "I believe the question whether the corona 

 is due to the terrestrial atmosphere is settled, and we have 

 before us the prospect of the study of the extra-solar regions, 

 which will be very interesting and fertile.' 7 



The spectroscope, the polariscope, and ordinary vision all 

 concur in supporting the explanation that the corona is com- 

 posed of solid particles and gaseous matter intermingled. It 

 fulfils exactly all the requirements of the hypothesis which at- 

 tributes it to the same materials as those which in a gaseous 

 state cause the reversion of the dark lines above described, but 

 which have been ejected with the great eruptions forming the 

 solar prominences, and have become condensed into glowing 

 metallic hailstones as their distance from the central heat has 

 increased. These must necessarily be accompanied by the 

 vapors of the more volatile materials, and should give out some 

 of the lighter gases, such as hydrogen, which, under greater 

 pressure, would be occluded within them, just as the hydrogen 

 gas occluded within the substance of the Lenarto meteor (a 

 mass of iron which fell from the sky upon the earth) was 

 extracted by the late Master of the Mint by means of his 

 mercurial air-pump. 



The rifts or gaps between the radial streamers, which 

 have been so often described and figured, but were regarded 

 by some as optical illusions, are now established as unquestion- 

 able facts. Mr. Lockyer, the last to be convinced, is now 

 compelled to admit this, which overthrows the supposition that 

 this solar appendage is a luminous solar atmosphere of any 

 kind. If it were gaseous or true vapor, it must obey the law 

 of gaseous diffusion, and could not present the phenomena of 

 bright radial streamers, with dark spaces between them, unless 

 it were in the course of very rapid radial motion either to or 

 from the sun. 



The photographs have not yet been published. When they 

 have all arrived, and can be compared, we shall learn some- 

 thing that I anticipate will be extremely interesting respecting 

 the changes of the corona, as they have been taken at the 

 different stations at different times. I alluded to this subject 

 before, when it was only a matter of possibility that such a 

 succession of pictures might have been taken. We now have 



