106 



prominences or protuberances, the subject-matter of the present 

 paper. Enveloping these and extending at times more than 

 a million miles into space, is the complicated structure called 

 the corona, with its streamers and rifts, clouds and filaments, 

 the aureola of glory seen round the sun in total solar eclipses. 



The first recorded observations of flames were made by 

 a mathematical professor at Gottenburg in Sweden, Birgen 

 Vassen by name, who during the eclipse of May 2, 1733, 

 noticed three red clouds suspended above the sun. Again, 

 in 1778, the attention of the Spanish Admiral, Don UUoa, when 

 observing the eclipse of that year, was attracted by a point of 

 red light on the western edge of the moon, which grew brighter 

 in proportion as the sun emerged, until it finally vanished. He 

 attributed this appearance to a hole in the body of the moon. 

 For some unaccountable reason these remarkable phenomena 

 seem to have entirely passed out of man's memory. Accordingly 

 their detection in 1842 by the eminent astronomers who 

 observed the eclipse of the 6th of July of that year, filled them 

 with surprise and wonder. The track of the moon's shadow in 

 this eclipse pased over Southern France Northern Italy, and 

 Austria. Observations of the flames were made, among others 

 by Baily and Airy, Arago, Scuhmacher and Biela, while at 

 Leipsic, Otto Struve saw again the rose-coloured chromosphere 

 closely surrounding the sun's limb, first discovered, according to 

 Flamsteed, by Captain Stannyen, on May 12, 1706. Various 

 hypotheses were at once set afloat to account for these novel 

 appearances. Some maintained that they were mountains on 

 the moon, seen by reflexion or refraction through a lunar atmos- 

 phere. Others again contended that they were true solar flames, 

 while a third party, including the learned M. Faye, asserted that 

 they were mere optical delusions, exactly analogous to the 

 terrestrial mirage. Nor was this discussion closed by the eclipse 

 of July 28, 1851. This time it occurred in Norway and Sweden, 

 and among the observers were Airy, Carrington, Hind, Dawes, 

 and others. Special watch was kept to see if the prominences were 

 gradually uncovered by the moon, a fact which ought to prove 

 their solar origin. No reasonable doubt was left on this point. 

 For example, in his observations Carrington describes the 

 gradual increase in size of three prominences on the western 

 limb of the sun. However, cavillers were not silenced ; M. 

 Faye still clung to the mirage theory. But the doubts of those 

 who were still unsatisfied were finally put to rest by the applica- 

 tion of photography to the eclipse which took place in Spain in 

 1860. To Mr. Warren de la Eue and to the late illustrious 

 director of the Roman College Observatory, Padre Secchi, is due 

 the honour of the settlement of the questions at issue. The 

 former of these two scientists was stationed at Eiva Bellosa, 



