﻿with Coloured Glasses and with the Spectroscope. 1 1 



doing great injustice to that element, as it has never given us 

 reason for bringing so grave a charge against it. Dr. Wedding, 

 in attempting to demonstrate that the non-appearance of the 

 manganese-lines is owing to the lack of sufficient quantity- 

 volatilized to produce its spectrum, makes the following state- 

 ments : — 



From analyses made by Brunner we find that the manga- 

 nese contained in the iron falls from 3 '460 per cent, in the raw 

 material to 1*645, 0*429, and finally to 0*113 per cent, in the 

 decarbonized product, and that the protoxide of manganese in 

 the slag first increases from 37*00 per cent, to 37*90 per cent., 

 and then sinks to 32*23 per cent., and, furthermore, that a certain 

 quantity of manganese is to be found in the smoke. How much 

 manganese is really lost by volatilization cannot be determined, 

 since data are wanting as to the absolute quantity of slag and 

 iron ; consequently we cannot determine how much manganese 

 has been lost by means of the eruptions. 



But since the manganese contained in the pig-iron decreases 

 constantly, 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. Comparing with this the experiments that 

 can be made in the laboratory, we arrive at the hypothesis 

 that the oxidized manganese which has entered into the slag 

 is not volatilized, but is retained by the slag ; it can therefore 

 get into the name only in the shape of solid or fluid combi- 

 nations. 



In the above statements the results of the analysis prove 

 that some of the manganese in the slag is volatilized. We 

 cannot consider the manganese-spectrum during the entire pro- 

 cess to be due wholly to the volatilization of the manganese directly 

 from the iron ; for while the amount eliminated from the iron 

 grows continually less, the manganese-spectrum grows brighter. 

 Owing to the intimate mixture by the blast of the iron aud 

 slag, the manganese oxide contained in the latter is brought 

 into contact with the melted iron and vaporized. This mixing 

 of the slag and iron would cease at the termination of the 

 process ; and this would account for the sudden diminution of 

 smoke. 



If there were a sufficient 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 manga- 

 nese spectrum. The^ Bessemer flame presents other problems 

 and opens an intensely interesting field for scientific investiga- 



