1078 
PROFESSOR W. N. HARTLEY ON 
Pig iron. 
Steel. 
Si ... . 2'5 per cent. 
S . . . . 0-04 
P . . . . OT to 0T2 per cent. 
Mil .... 2'6 ,, 4‘0 ,, 
C . . . . 3'5 per cent. 
Si ... . 0'4 to O'7 per cent. 
S .... 0'06 per cent. 
P . . . . O'l to 0'15 per cent. 
Mn .... 0'4 ,, 0'7 „ 
C .... O'15 per cent. 
The indication of the close of the process differs from that in ordinary work, for 
whereas the spectroscope usually gives distinct indications during the “ fining stage,” 
with manganiferoLis pig it is much more difficult to make use of it to advantage. 
The excessively brilliant flame due to the combustion of manganese vapour 
necessitates the use of dark blue glasses to protect the eyesight of the operator. 
When the metal is decarburized a thick smoke of brown oxides rises out of the bath, 
and finally becomes so dense that it hides all other indications. But before this 
moment has arrived the lines in the blue disappear, the bands in the green grow 
weaker and then disappear, while those in the yellow become weaker. When all 
the bands have vanished the spectrum becomes continuous. 
The blast is continued for a minute or two longer to decarburize the metal as 
completely as possible, and a sample of slag and metal is removed from the converter 
by thrusting a wrought-iron bar into the bath ; from the appearance of these samples 
the nature of the metal is ascertained. 
This brown smoke of oxides has been noticed by Dr. Muller, of Osnabriick (‘Le 
Genie Civil,’ vol. l,p, 25, 1880), when the converter is inclined so that some air passes 
over the surface of the bath of metal ; it is, therefore, due to oxidation. 
I have observed such fume to be produced in enormous volumes when the charge 
has become too hot, and the converter is turned down during the “ boil,” so that the 
blast instead of passing througli the molten metal passes over its surface and sweeps 
out the vapours of iron and manganese. Clouds of foxy-red smoke produced in tliis 
manner I have seen rise to a height estimated to be at least 200, and even 300 feet. 
The smoke is composed of little spherular particles containing oxides of iron and 
manganese. 
There can be no doubt that Wedding was, in the main, correct in considering that 
the non-appearance of the lines of manganese at the commencement and termina¬ 
tion of the “ blow ” is owing to the fact that the quantity of material volatilised at 
these periods is insufficient for the production of a spectrum ; but it may also be 
due, at the close of the process, to the oxidising atmosphere wdthin the converter. 
The spectroscopic phenomena of the blow are undoubtedly determined by the 
diemical composition of the gaseous contents of the converter and of the bath of 
metal, the temperature of the metal, and of the issuing gases. The etfect of rise of 
te}nperature is to increase the volatilisation of manganese and iron. 
