CHAPTEK V. 



SPECTROSCOPIC OBSERVATIONS. 



THE object of observing a total eclipse of the sun is of course 

 to increase our knowledge of those surroundings and 

 appendages of the sun which are then, and then only, revealed 

 to us. So intense is the glare surrounding the sun on ordinary 

 occasions, from the lighting up of our atmosphere in his 

 immediate neighbourhood, that the whole of the beautiful and 

 complicated objects which form, as it were, the pavilion in 

 which he perpetually abides, are entirely hidden from us in 

 ordinary daylight. Though very bright themselves, they are 

 drowned in the far greater brightness of the atmospheric glare. 

 And this glare renders it impossible for us to bring the sun's 

 surroundings into view by arranging a kind of artificial eclipse ; 

 or else it would be easy enough to form an image of the sun and 

 its appendages in the focus of a telescope, and then, hiding the 

 sun itself behind an opaque disk, to examine its neighbourhood 

 at leisure. 



Up to the eclipse of '1842, July 8, very little notice had 

 been taken of the revelations which solar eclipses afforded of 

 strange and beautiful objects apparently surrounding the dark 

 body of the moon, and which might belong either to her, or to 

 the sun which she at such times concealed for a brief interval. 

 But in that year the shadow track passed over the entire length 

 of Europe, and all the first astronomers of the day were induced 

 to take part, in its observation, and the attention of every 

 observer of that eclipse was caught by the beautiful rose or ruby 

 coloured lights of irregular forms and distribution, which were 

 seen round the dark moon. From that time forth, "the red- 

 flames," " prominences " or " protuberances " as they have been 

 variously called, have been as thoroughly enrolled amongst the 

 objects of astronomical interest as comets or nebulae. 



Nine years later the shadow track of another eclipse, that of 

 1851, July 28, passed across Europe, but from north to south, 

 not west to east as in 1 842, and the prominences received yet 

 further attention. It was then made clear, as the acuter 

 observers in 1842 had inferred, that they belong to the sun, 

 not to the moon ; and it was also seen that they rise up from 



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