RECENT SOLAR RESEARCHES. 8 1 



firmation of the justice of this opinion. He and Jannsen 

 had independently shown that the existence of promi- 

 nences can be recognised when the sun is not eclipsed ; 

 and the same method supplied clear evidence of the 

 existence of this red envelope, to which Mr. Lockyer 

 gave the name of the Chromosphere. Remembering who 

 first indicated its existence as ' indisputable,' we may 

 conveniently call it Secchi's Chromosphere. (See note 

 at the end of this paper.) 



Both the chromosphere and the prominences consist 

 of glowing vapour. But there is a difference in their 

 constitution. In the prominences there are usually but 

 very few constituent vapours. Hydrogen is there, and 

 another vapour, whose nature is as yet undetermined, 

 while occasionally there are the vapours of other ele- 

 ments. But in the chromosphere there are commonly 

 several elements, and sometimes there are many. 



Here, then, we have above the photosphere of the 

 sun a vaporous envelope, obviously of a complicated 

 structure, and perhaps far more complicated than it has 

 yet been proved to be. For it must be remembered 

 that the lowest layers of this envelope might be com- 

 posed of the vapours of numerous elements, and yet no 

 record of their existence be recognised. A depth of 

 ten miles would correspond to so small a proportion of 

 the sun's diameter (about the 85,000th part) as to be 

 wholly unrecognisable by any telescopic power men 

 can hope to obtain. If any of our readers are tele- 

 scopists, they will know what force lies in the remark 

 that such a distance would subtend about the 44th 



