70 The Greed Solar Eclipse [Jan., 



great variations in the height and luminous power of the different 

 regions of the protuberance. Shortly afterwards I perceived that 

 the brilliant ray f was visible as well as g. In the afternoon I 

 returned to the region examined ui the morning ; the brilliant 

 Hnes showed that great changes had taken place in the distribution 

 of the matter of the protuberances ; the liaes were sometimes broken 

 iato isolated parts which were not united with the principal line in 

 spite of the movements of the exploring sHt. This fact indicated 

 the existence of isolated clouds which had been formed during the 

 morning." 



The conclusion of M. Janssen's report contains two interesting 

 facts, the first is that the hnes of the protuberances penetrate into 

 the black hnes of the solar spectrum, thus demonstrating the pro- 

 longation of the protuberances on to the globe of the sun. The 

 second is that the protuberances become altered in shape and dis- 

 placed with extreme rapidity. On the 4th of September a remark- 

 able observation is recorded, showing that a mass of matter many 

 hundred times larger than the earth is in a few moments displaced 

 and completely altered in form. 



This discovery of M. Janssen's was strangely enough com- 

 municated to the French Academy only a few minutes after 

 Dr. De la Eue had communicated Mr. Lockyer's discovery to the 

 same body ; it had before been communicated to the Eoyal Society. 

 As Mr. Balfour Stewart remarks: — "Although the priority of 

 observation is due to M. Janssen, yet the possibility of the discovery 

 was suggested by Mr. Lockyer more than two years ago, and to my 

 knowledge he has been working at it since that time; whereas M. 

 Janssen frankly acknowledges that the idea only occurred to him 

 during the eclipse itself. This fact was very nobly referred to by 

 M. Faye, at the discussion wliich followed the announcement of the 

 discovery at the Academy of Sciences." 



It would appear as if these luminous lines were somewhat 

 variable in then appearance, some being present in one protuber- 

 ance and not in others. The temperature and intensity of action 

 going on over the sun's surface have also much to do with their 

 appearance ; thus Mr. Lockyer has occasionally detected a new c 

 line, a little less refrangible than c by the distance apart of the two 

 D Hnes, a]iparently caused by an ejection of extraneous matter. A 

 curious phenomenon has also occasionally been observed with the f 

 Hue, it sometimes exhibits a widening at the base or in some other 

 portion of its length, suggesting the explanation that with great 

 increase of temperature the ray of light of this rcfi'angibility 

 becomes nebulous and capable of spreading sideways, in the same 

 way as the yellow sodium lines wUl do. No other line has been 

 observed to do this. 



In the colom-ed illustration the lowest spectrum shows Mr. 



