98 Mr. W. N. Hartley. On the Origin of some of the Lines 



Per cent, 

 carbon. 



The aspect of the spectrum. 



l-2\ 



The group £ just disappearing, the group 8 very dis- 



1-1 J 



tinct. 



1 U 



The group d a little fainter. 



*90 



„ „ yet fainter. 

 $3 and $4 fainter than other bands of the group. 



U OK) 



0-75 



£ 3 and $ 4 indistinct. 



f£ JUBt LliodjUJJttXl xSKXm 



*70 



0-55 



8 3 and 5 4 are away. 



0-40 



The group d away. 



0-20 



The group d x y s , j3 2 and generally y 2 are away. 



Subsequently no constant values were obtained, but on judging 

 from similar spectra, on one occasion the metal contained 0*95, and 

 another time 0'65 per cent, of carbon. The sole change that had 

 been made was due to the slit of the instrument having been cleaned. 

 This indicates that it may be of some importance to have this so 

 regulated by a micrometer-screw that its width may be accurately 

 determined at any time during a series of observations. The tempe- 

 rature of the iron of the converter may have some influence upon 

 the disappearance of the bands, as similarly bands already described 

 appear during the " blow " more distinctly if the temperature is high 

 than if it is low. 



" Remarks on the Origin of some of the Lines and Bands 

 observed in the Spectra from Swedish Bessemer Works." 

 By W. N. Hartley, F.R.S. Received April 1, — Read June 

 20, 1895. 



The observations made at various Bessemer steel works in Sweden, 

 as described in the preceding paper, are of particular interest, owing 

 to the number of accurate measurements of bands and lines observed 

 in different spectra of the flame during the progress of the " blow " 

 when different varieties of metal are operated upon. 



As the paper was written, as I have been informed by Mr. Lund- 

 strom, about nine years ago, the author was at a disadvantage in 

 being unable to compare all his measurements with flame spectra of 

 known origin at high temperatures. Fallacious deductions are liable 

 to be drawn by referring bands and lines in the Bessemer flame to 

 only such spectra as have been obtained by the arc or spark. This 

 was found to be the case in the study of oxyhydrogen blow-pipe 

 spectra (' Phil, Trans, vol. 185, A, p. 161) ; hence I propose to offer 



