﻿with Coloured Glasses and with the Spectroscope. 5 



bright lines or absorption-bands, nor was any coincidence ob- 

 served between the lines of the Bessemer spectrum and those 

 of the carbonic-oxide vacuum-tube. The lines of lithium, 

 sodium, and potassium were strongly marked, and identified 

 with certainty. He found that three fine bright lines between 

 E and b, shown on the plate at 66J°, 67°, and 67^°, coincided 

 with those of iron ; and in place of the red hydrogen-line C he 

 discovered a black band which he considered an absorption- 

 band, and states that it is better defined in wet than in dry 

 weather. 



In Austria Professor Lielegg followed up this subject with 

 great perseverance, and gave more extended accounts of the 

 varying character of the Bessemer spectrum during the different 

 stages of the process. His experiments were made at Gratz, 

 where the spectroscope was afterwards used with great success 

 in controlling the Bessemer process; but at Konigshutte, 

 where dark grey manganiferous iron was used, it was found that 

 the indications which in other works so plainly determined the 

 moment of decarbonization were unreliable. In this case the 

 lines, whose disappearance is to indicate the exact point of time 

 for ending the process, disappear too soon. During the period 

 in which the spectrum is brightest, among the glowing vapours 

 and gases that stream from the converter, carbonic oxide, next 

 to nitrogen, is most abundant ; and it is for this reason that 

 the first investigator (Roscoe) expressed himself as confident 

 that the numerous lines of the spectrum were caused by this 

 gas, although he could obtain no coincidence. 



Brunner* states that "no part of the Bessemer spectrum is 

 ever visible in the flame when the converter is heated for the 

 first time after being relined, but, that when the lining is not 

 new, Lielegg's group of green lines (CO7) appears in the spec- 

 trum, which then contains also the lines of potassium, sodium, 

 and lithium," — from which he concludes that this spectrum is 

 not to be identified with carbonic oxide, but must be produced 

 by other constituents of pig iron. Others state that the Bes- 

 semer spectrum is sometimes visible while the converter is being 

 heated after a blow. I made an observation of the flame from 

 the converter while it was being heated the first time after being 

 relined, and obtained with great distinctness the potassium-, 

 lithium, and sodium-lines, but have not under any circumstances 

 detected any other lines while the converter was being reheated. 



Lichtenfels, by a series of simultaneous comparisons of the 



manganese with the Bessemer spectrum, found the lines in the 



blue and green fields to completely harmonize in the two spectra. 



The violet manganese-line which had been seen by some he 



* Van Nostrand's Eclectic Eng. Mag., vol. i. p. 508. 



