THE SUN. 53 



sun-flames. During the progress of the eclipse, 

 Janssen was specially struck by the brilliancy 

 of the bright lines, and it occurred to him that 

 the prominence -spectrum could be observed in 

 full daylight, if sufficient dispersive power was 

 used to enfeeble the ordinary continuous spec- 

 trum. At ten o'clock on the following morning, 

 August 19, 1868, Janssen applied his spectro- 

 scope to the sun, and observed the prominence- 

 spectrum. After a month's observation in India, 

 he sent to the French Academy an account of 

 his success. A short time, however, before his 

 report arrived, the Academy had received a 

 similar one from Lockyer, who had independently 

 made the same discovery. Two years previously, 

 in 1866, the new method had occurred to him, 

 but his spectroscope was not powerful enough ; 

 and although he ordered a more powerful one 

 at once, it was not until October 16, 1868, 

 that he had the instrument in his hands. Four 

 days later he observed the prominence-spectrum 

 in full daylight. 



The next advance in the study of the promi- 

 nences was announced in 1869. Janssen and 

 Lockyer had shown astronomers how to observe 

 the spectrum of the prominences ; but the re- 

 searches of other two famous astronomers enabled 

 observers to see the forms of the prominences. 



