THE ECLIPSE OF 1870. 53 



astronomers. They recognised the corona, and they 

 justly regarded it as the cause, 'of that light which still 

 remains when the sun's globe is wholly concealed from 

 view ; but they formed no theories as to the physical 

 significance of this aureole of light. 



Indeed, if we are to reach the time when systematic 

 observations have been made upon the sun with the 

 express object of determining the nature of those 

 appendages which come into view during total eclipse, 

 we must pass over not merely the whole of ancient 

 astronomy, but almost the whole of that portion of the 

 history of modern astronomy which refers to epochs 

 preceding the last thirty years or so. 



It was when the eclipse of 1842 was approaching, 

 that for the first time astronomers aroused themselves 

 to a sense of the real importance of the phenomena 

 presented during total eclipse. Then, for the first 

 time, astronomers of repute, armed with instruments 

 of adequate power, placed themselves along the track 

 which the moon's black shadow was to pursue, and 

 severally prepared to glean what knowledge they might 

 respecting the physical habitudes of the solar sur- 

 roundings. 



The expeditions made in 1842 were abundantly 

 rewarded. For it was during that great total eclipse 

 that the coloured prominences were first fairly recog- 

 nised. More than a century before Vassenius had 

 suspected the existence of some red objects near the 

 eclipsed sun. But strangely enough small attention 

 had been paid to his remarks. And accordingly, the 



