ASTRONOMY. 17 



chromosphere; but when the moon had covered the chromo- 

 sphere, there was only a disappointing continuous band of 

 color, unmarked by rings of any kind. 



"Those, also, who were looking for new bright lines in the 

 corona spectrum were equally unsuccessful, whether they 

 employed the ordinary spectroscope or worked by photogra- 

 phy. Some of the observers, the writer among others, used 

 a so-called 'fluorescent eye-piece,' which brings the other- 

 wise invisible light beyond the extreme violet end of the 

 spectrum within the range of the human eye by the action 

 of a film of fluorescent liquid (sesculia solution) enclosed be- 

 tween thin plates of glass. But, although before totality the 

 apparatus worked perfectly, disclosing to the eye dark lines 

 innumerable in the portion of the spectrum invisible without 

 its aid, after the darkness came on it failed to show a single 

 bright line. The most carefully prepared and sensitive pho- 

 tographic apparatus succeeded no better, except that Dr. 

 Draper, Mr. Lockyer, and one or two others perhaps, did ob- 

 tain, by means of a slitless spectroscope, an impression of a 

 faint continuous spectrum in the ultra violet, without rings 

 or markings of any kind. Evidently no lines existed to see 

 or photograph on this occasion. 



" One or two observations were made of some interest in 

 their relation to previous work. Professor Rockwood, of the 

 Princeton party, using a double-barrelled slitless spectro- 

 scope, observed at the beginning of totality a bright-red line 

 in the chromosphere spectrum very near to B. This explains 

 an observation of Mr. Pogson in 1868, who then insisted that 

 lie saw B reversed in the spectrum of a prominence; but as 

 all the other observers had C instead of B, his record was 

 generally regarded as a mistake. 



"The line is probably one well known to solar spectro- 

 scopists as 534 of Kirchhoff's scale a line exceedingly diffi- 

 cult to see in the spectrum of the chromosphere under ordi- 

 nary circumstances, but still invariably present. Its conspic- 

 uousness in Professor Rockwood's instrument is a matter of 

 some surprise; but there could be no mistake, as C was even 

 more brilliantly conspicuous at the same time. What the 

 substance which causes it may be is quite unknown. Like 

 the so-called D 3 line, it has no corresponding dark line in the 

 solar spectrum. 



