320 



NA TURE 



[August 5, 1897 



iron, that two lines in the visible spectrum at 4924'i and 

 501 8"6, on Rowland's scale, were greatly enhanced in 

 brightness with higher temperatures, and were very im- 



observed in other parts of the photosphere, so we should 

 not expect to find the hotter lines so frequent in them. 

 Fig. II gives the facts. It is a comparison of the iron 



SPARK THALEN 



REQUENCIES 



SUN SPOTS 



UJ KENSINGTON 



•REQUENCIES 



W\ PALERMO 



-Iron spot-lines seen at Kensington confronted with iron prominence lines seen at Palermo. 



por'.ant in solar phenomena. Thus the line at 4924T 

 was at times the only representative of ircn in the chromo- 



lines observed in spots, and in the quiet chromosphere 

 during the same time in 1872, the spots being observed 



raunhofer lines. 



/Angstrom. 

 Uron aic. 



/Iron spark. 

 (Thalen (corrected). 



Lines intensified in spark. 



Prominence lines, Tacchlni 



Spot lines, Lockyer. 



7 min. before totality 



Fig. 12. — The line seen during the Solar Ejlipiein 1882 

 before totality, and some of the spot lines were not ; 



showing that the prominence lin: at 4924-1 was seei 

 ;en till two minutes before totality, and then they ' 



Egyptiai 

 i eclipse. 



short and bright seven minutes 

 'ere observed long and dim. 



sphere ; upwards of iocxd lines in the visible spectrum of 

 iron gave no sign. 



Spots are conceded to be cooler phenomena than those 

 NO. 1449, VOL. 56] 



at Kensington, the chromosphere at Palermo. It will 

 be seen that none of the lines seen in the chromosphere 

 were seen in the spots, and vice versa. 



