1074 
PROFBSSOTl W. N. HARTLEY ON 
Bunsen flame, of a milligramme of manganese can be detected (Simmler) ; but 
tlie quantity of alkalies is much smaller—as, for instance, scroo^h of a milligramme of 
potassium, -goo^oof^^ of lithium, and 1-470^07000^^1 of sodium (Kirchhof). The 
flame spectrum of manganese is almost entirely a banded spectrum, the peculiarities 
of which had not been investigated at that time. 
SiLLTMAN had urged against this view of Wedding :—1st, If the disappearance of 
the manganese lines in the Bessemer spectrum be owing to the diminution of the 
quantity of manganese, we should infer that these lines would gradually grow more 
indistinct, and then fade away ; but the fact is the contrary—the manganese spectrum 
increases in brilliancy from its first appearance, and is more intense just before being 
swept away than at any other time. The analysis of the fume which appears when 
the flame ceases, proves that a considerable quantity of manganese is still volatilized ; 
and it is notable that in manganiferous iron this quantity increases towards the close 
of the ‘‘ blow.” 2nd. It would be more difficult to account by this theory for the 
non-appearance of the sodium line at the beginning 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 sjiecial precautions that we can keep it out of 
any flame. 3rd, A still greater difficulty would arise in applying this theory to the 
spectra of sodium and hthium at the close of the “ blow.” As has been stated, these 
lines sometimes disappear at the moment of complete decarburization, and sometimes 
remain. In the former case to say that the sodium had been exhausted would not be 
in accordance with what we know of that element. 
Wedding based his explanation of the non-appearance of the manganese lines upon 
the analysis made by Brunner. It was found that the manganese contained in the 
iron fell from 3'46 per cent, in the pig to 1’64.5, 0'429, and finally to 0‘113 per cent, 
in the decarburized product; and that the manganous oxide in the slag first increased 
from 37’00 to 37‘90 per cent., and then sank to 32’23 per cent. ; and, furthermore, 
that a certain amount of manganese is to be found in the fume. 
SiLLiMAN states that since the manganese contained in the pig iron decreases con¬ 
tinuously, and that contained in the slag after the termination of the boiling period 
also decreases, a considerable volatilization of this body is probable, just at the time 
when the spectrum is best developed. Wedding found from Brunner’s analysis 
that some of the manganese is volatilized from the slag, and it was further considered 
that the manganese spectrum during the entire process cannot be due wholly to the 
volatilization of manganese directly from the iron ; for while the amount eliminated 
from the iron grows continually less, the manganese spectrum grows brighter. If 
there were a sufficiently large quantity of carbonic oxide flame to render the escaping 
gases glowing, it is evident they would not issue from the converter as dark smoke, 
but as incandescent vapour, having its characteristic spectrum. The lack of sufficient 
flame may therefore account for the disappearance of the manganese spectrum. 
Against Sfleiman’s criticism of Wedding’s arguments it may be urged that, 
