THE ECLIPSE OF 1878. 133 



since it emits at least as much light as it absorbs. I 

 would recommend to the special attention of spectro- 

 scopists a re-examination of the solar spectrum in the 

 region of this line ; for, as will presently appear, the 

 sun's surroundings are not now in the same condition 

 as*" they were in 1869, 1870, and 1871, when special 

 search was made for the 1474 line. The statement 

 that both the H lines were reversed is important, as 

 showing that the whole range of the visible spectrum 

 was examined for these reversed or bright lines. The 

 H lines are near the violet end of the spectrum. They 

 belong to calcium, and, as calcium has been recognised 

 at times in the sierra, we can hardly attach special 

 importance to the fact that these lines were seen in 

 the more complex spectrum of the solar atmosphere 

 below the sierra. The observation was probably only 

 mentioned to show that the array of bright lines was 

 traced up to the violet end of the spectrum. Indeed, 

 quite possibly the bright lines near B were only 

 mentioned for a similar reason, B lying at about the 

 same distance from the red end of the spectrum as H 

 from the violet end. 



Turning next to the sierra, or chromatosphere, we 

 learn that on this occasion its height was far less than 

 in 1869-1871. A query is attached to the height, 

 2,000 miles, mentioned in the telegram ; but probably 

 the doubt related to the number of ciphers only, not 

 to the ' 2,' and if so, we need not concern ourselves 

 with it ; for unquestionably the sierra was not so high 

 as 20,000 miles, nor so low as 200 miles, the former 



