xxviii President's Address 



extremely satisfactory, and the mystery of those wonderful 

 red or rose-coloured prominences which during the moments 

 of totality have been seen to jet out from or hover over the 

 sun's edge, and which had hitherto puzzled astronomers and 

 physicists, was to a great extent unravelled. 



The spectroscope revealed in their light the well known 

 lines of hydrogen. Every observer told the same story — 

 hydrogen lines, the light of incandescent hydrogen. These 

 beautiful rose-coloured prominences, therefore, appear to be 

 jets and clouds of red-hot hydrogen of enormous dimensions, 

 some of which are sometimes projected nearly 100,000 miles 

 into space. 



Almost immediately after the eclipse two astronomers — 

 M. Janssen in India, and Mr. Lockyer in England — 

 independently discovered that these red flames could be 

 seen at almost any time, and that no total eclipse was 

 necessary to render them observable and measurable, and to 

 bring them within the reach of the searching analysis of the 

 prism. With the spectroscope specially arranged on a 

 telescope these phenomena could be seen almost at any time. 

 This discovery gave a new impetus and direction to the 

 physical investigation of the sun's surface, and opened up 

 new fields and methods of research which have added very 

 largely to our knowledge of the physical constitution of our 

 great luminary. 



It had long since been shown by spectrum analysis in 

 the hands of Kirchhoff, Bunsen, and others, that the visible 

 surface of the sun or photosphere contained the incandescent 

 vapours of many of the metals, earths, and gases, which exist 

 in our globe ; and careful observers have noted the mobile 

 condition of it, more especially in the neighbourhood of spots, 

 where the vaporous masses are often seen to move with 

 terrific speed in cyclonic whirls. Now, the behaviour of 

 these vapours can be seen in profile around the sun's -edge. 



