5oo HISTORY OF SCIENCE. 



in Fig. 227 somewhat as they appeared in the total eclipse of 1869. 

 The first distinct record of the red prominences is contained in a letter 

 addressed to Flamstead by an observer of the eclipse of 1706. They 

 were seen again in 1715, and in almost every total eclipse since, as 

 well as in some partial eclipses. Some observers attributed the " red 

 flames " to the moon and others to the sun, and it was not until the 

 total eclipse of 1860, when the red .flames were very distinctly seen at 



FIG. 227. SOLAR ECLIPSE, 1869. 



many stations, that it was conclusively proved they belonged to the sun 

 and not to the moon. 



In 1866 Mr. Norman Lockyer suggested that by the use of the spec- 

 troscope it might be possible to obtain evidence of the presence of 

 the red prominences without waiting for solar eclipses. But it was 

 not until two years afterwards that Mr. Lockyer was able to realize his 

 idea. On the 2oth of October, 1868, he succeeded in obtaining the 

 spectrum of a red prominence, and this spectrum he found to consist 

 of three bright lines, one exactly coincident with Fraunhofer's c, the 

 second nearly coincident with F, and the third near D. Strangely 

 enough, the same discovery had just been made independently in a 

 distant part of the world, though the French Academy of Sciences 

 received the communication a few days after Lockyer had announced 

 his results to the Royal Society. The French Government* had sent 

 M. Janssen to India to observe at Guntoor the total eclipse of the 

 sun on the i8th of August. M. Janssen mentions that during the 

 totality two fine red prominences were visible, one of which subtended 

 an angle of more that 3', and therefore must have been 90,000 miles 

 in height. The spectroscope showed that this object was an immense 

 column of incandescent hydrogen gas. During the progress of the 

 eclipse, a method of observing the red prominences independent of 



