On the Iron Lines present in the Hottest Stars. 475 



" On the Iron Lines present in the Hottest Stars. Preliminary 

 Note." By J. NORMAN LOCKYER, C.B., F.R.S. Received 

 January 25, Read February 18, 1897. 



In continuation of investigations communicated to the Royal 

 Society in 1879* and 1881, f on the effect of high-tension electricity 

 on the line spectra of metals, I have recently used a more powerful 

 current and larger jar surface than that I formerly employed. 



The former work consisted in noting (1) the lines brightened in 

 passing a spark in a flame charged with metallic vapours, and (2) the 

 lines brightened on passing from the arc to the spark. It was found, in 

 the case of iron, that two lines in the visible spectrum at 4924*1 and 

 5018'6, on Rowland's scale, were greatly enhanced in brightness, and 

 were very important in solar phenomena. 



The recent work carries these results into the photographic region. 

 The result is interesting and important, since seven additional lines 

 have been found to have their brightness enhanced at the highest 

 temperature. These, as well as the two previously observed, are 

 shown in the following table, which also indicates the behaviour of 

 the lines under different conditions, as observed by Kayser and 

 Runge (K and R) and myself (L) in the arc, and by Thalen (T) 

 and myself in sparks : 



Lines of Iron which are enhanced in Spark. 



Combining this with former results, we seem justified in conclud- 

 ing that, in a space heated to the temperature of the hottest spark, 

 and shielded from a lower temperature, these lines would constitute 

 the spectrum of iron. 



* < Roy. Soc. Proc.,' 1879, vol. 30, p. 22. 

 f Ibid., 1881, Tol. 32, p. 204. 



