Dr. Watts on the Spectrum of the Bessemer-flame. 439 



The occurrence of ahsorption-lines in the Bessemer-spectrum is 

 in itself extremely probable ; and that this is the case appears 

 almost proved by the great intensity of some of the dark lines of 

 the spectrum. It was with this view that the investigation was 

 commenced, with the expectation that the spectrum would prove 

 to be a compound one, in which the lines of iron, carbon, or car- 

 bonic oxide &c. would be found, some as bright lines, others 

 reversed as dark absorption-bands. To a certain extent this an- 

 ticipation has been verified ; but the great mass of the lines, in- 

 cluding the brightest in the whole spectrum, have not as yet been 

 identified. 



In dealing with a complicated spectrum like that of the Bes- 

 semer-flame, it is indispensable that the spectrum should be 

 actually compared with each separate spectrum of the elements 

 sought. This was the plan actually pursued ; the spectroscope 

 was so arranged that the spectrum of the Bessemer-flame was 

 seen in the upper half of the field of view, and the spectrum 

 with which it was to be compared was seen immediately below. 

 In no other way can any satisfactory conclusion be obtained as 

 to the coincidence or non-coincidence of the lines with those of 

 known spectra. 



The spectrum of the Bessemer-flame was thus compared with 

 the following spectra : — 



(1) Spectrum of electric discharge in a carbonic-oxide vacuum. 



(2) Spectrum of strong spark between silver poles in air. 



(3) „ „ iron „ 



(4) „ „ iron poles in hydrogen. 



(5) Solar spectrum. 



(6) Carbon spectrum — oxyhydrogen blowpipe supplied with 

 olefiant gas and oxygen. 



The coincidences observed were, however, but very few, and 

 totally failed to explain the nature of the Bessemer-spectrum. 

 The lines of the well-known carbon-spectrum (given in fig. 1) do 

 not occur at all, either as bright lines or as absorption-bands ; 

 nor was any coincidence observed between the lines of the Bes- 

 semer-spectrum and those of the carbonic-oxide vacuum-tube. 



The lines of lithium, sodium, and potassium are always seen 

 and are unmistakeable. 



The three fine bright lines 73*7, 76*8, and 82 are due to iron. 

 The red band of hydrogen (C) is seen as a black band, more 

 prominent in wet weather. 



After the charge of iron has been blown it is run into the 

 ladle, and a certain quantity of the highly carbonized spiegel- 

 eisen is run into it. The effect of the addition of the spiegel- 

 eisen is the production of a flame which is larger and stronger 

 when the blow has been carried rather far. This flame occasion- 



