306 J. M. Silliman—Examination of the Bessemer Flame. 
presence of a certain quantity. And although manganese is al- 
ways left in the iron, it may not be left in sufficient quantity at 
the termination of the blow to produce the spectrum, and for 
this reason the lines disappear.” 
To this theory there are same some strong objections. 1sé. If 
we take manganese in sufficient quantity and hold it in a flame 
theory for the non-appearance of the sodium line at the begin- 
ning of the blow, as sodium then in all probability exists 
in the issuing gas in sufficient quantity to produce its spectrum 
at a high temperature, as it is only by special precaution that 
we can keep it out from any flame. 8rd. A still greater diffi- 
culty would arise in applying this theory to the spectra of sodium 
and lithium at the close of the blow. As has before been stated, 
these lines sometimes disappear at the moment of complete 
decarbonization, and sometimes remain. In the former case, to 
‘Se 
