1044 
PROFESSOR W. N. HARTLEY OX 
It was noticed that after lines of the alkali metals had become visible, an immense 
number of lines were seen, some as fine bright lines, others as intensely dark bands. 
Striking evidence was afforded of the cessation of the removal of carbon from the 
iron by the disappearance of nearly all the dark lines and most of the bright ones. 
The spectrum was stated to be remarkable from the total absence of lines in the 
more refrangible portion; it extended scarcely beyond the solar line It was 
found indispensable that the spectrum should be actually compared with the spectra 
of the elements sought for. The spectrum of the Bessemer flame was accordingly 
compared with the following sjrectra :— 
(1.) Spectrum of electric discharges in a carbonic oxide vacuum. 
(2.) Spectrum of strong spark between silver poles in air. 
(3.) Spectrum of strong spark between iron poles in air. 
(4.) The same in liydrogen. 
(5.) Solar spectrum. 
(G.) Carbon spectrum, oxy-hydrogen blow-pipe supplied with olefiant gas and 
oxygen. 
The coincidences observed were very few and totally failed to explain the nature 
of the Bessemer sjDectrum. 
The spectra of neither carbon, nor of carbonic oxide," appeared in the Bessemer 
flame, eitlier as bright lines or as absorption bands. Three lines were traced to iron 
and a dark absorption band in the red, due to hydrogen (line C), was visible more 
particularly in wet weather. 
J. M. SiLLiMAN (‘ Phil. Mag.,’ vol. 41, p. l) pointed out that the progress of the 
decarburization in the Bessemer process is determined chiefly by the apj^earance of 
the smoke, flame, and sparks emitted from the converter, and that owing to the 
rapidity with which the changes takes place it is highly important to catch the exact 
moment when the blast should be tinned off. The colour and brightness of the 
stream of gas issuing from the converter when observed by an experienced eye, 
generally give a sufficient indication, but when pig iron of a highly manganiferous 
character is used, this determination is very difficult; even those who had had much 
experience made frequent mistakes, and found it impossible to produce the same 
quality of metal at every operation. 
Mr. PtOWAN, of the Atlas Works, Sheffield, made use of coloured glasses, two of 
ultramarine blue and one of dark yellow, by which the eye was greatly assisted and 
the termination of the process rendered unmistakeable. 
Though Lielegg first recognised the fact that the spectrum of the Bessemer flame 
was not the spectrum of carbon, nor entirely that of carbonic oxide, which giwes a 
continuous spectrum, it wars Brunner in 1868 who first expressed the view that the 
* It does not appear that Watts examined the flame of carbon monoxide burnt with air or with 
oxygen. 
