Dr. Watts on the Spectrum of the Bessemer- flame. 437 



of a single cause manifesting itself in various forms. But it is 

 a long way from this to the discovery of this cause, this single 

 force. Shall we some day arrive at it ? It is possible and even 

 probable ; and in this case the name and the works of Faraday 

 will always remain associated with one of the greatest problems 

 which the human mind can entertain. 



LV. On the Spectrum of the Bessemer-flame. 

 By W. M. Watts, D.Sc* 



[With a Plate.] 



THE October Number of the Philosophical Magazine contains 

 translations of two papers by Professor Lielegg, giving the 

 results of his observations on the spectrum of the Bessemer- 

 flame. As these results are published as entirely new and no 

 mention is made of any prior observations, it is only right that 

 attention should be called to the fact that as long ago as 1862 

 the same results had been obtained by Professor Roscoe, and 

 were published in the form of a short preliminary notice in the 

 c Proceedings ' of the Manchester Literary and Philosophical 

 Society for February 24th, 1863. As the note is extremely short, 

 I venture to transcribe it in full. 



" Professor Roscoe stated that he had been for some little time, 

 and is still, engaged in an interesting examination of the spec- 

 trum produced by the flame evolved in the manufacture of cast 

 steel by the Bessemer process, on the works of Messrs. John 

 Brown and Co., of Sheffield. The spectrum of this highly lumi- 

 nous and peculiar flame exhibits during a certain phase of its 

 existence a complicated but most characteristic series of bright 

 lines and dark absorption-bands. Amongst the former the sodium, 

 lithium, and potassium lines are most conspicuous ; but these are 

 accompanied by a number of other, and as yet undetermined, 

 bright lines; whilst among the absorption-bands those formed 

 by sodium-vapour and carbonic oxide can be readily distin- 

 guished. Professor Koscoe expressed his belief that this first 

 practical application of the spectrum analysis will prove of the 

 highest importance in the manufacture of cast steel by the Bes- 

 semer process, and he hoped on a future occasion to be in a posi- 

 tion to bring the subject before the Society in a more extended 

 form than he was at present able to do." 



In a lecture delivered before the Royal Institution (May 6, 1864) 

 a year later than the communication quoted above, Dr. Roscoe 

 described the Bessemer spectrum more fully, and pointed out the 



* Communicated by the Author. 



