160 



BULLETIN 42, UNITED STATES NATIONAL MUSEUM. 



purity of the ores used and partly due to the skill displayed in carrying 

 on the works. 



The iron ores and limestone employed at the charcoal blast furnaces 

 at Westanfors and Fagersta consist of the following component parts: 



Iron ore fioni tlio mines of- 



Silica(Si02) 



Alumina (Al^Oj) 



Lime(CaO) 



Magnesia (MgO) 



Protoxide of manganese (MnO) 



Protoxide of iron (FeO) 



Sesquioxide of iron (FejOj) 



Carbonic acid (CO.;) , 



Phosplioric acid (P^Oj) , 



i Ostra 

 1 Stortai;ten. 



27. 49 

 1.30 

 2.10 

 1. 70 

 0.81 

 20.74 

 46. U 



Granrot. Grondal 



3. 10 



2.05 



1.20 



1.0.-) 



10.40 



23. 5G 



5.'. 44 



6.10 



0.009 



99. 909 



6.35 



1.15 



2. 65 



3.85 



5.50 

 22. 82 

 50.78 



5.95 



0.014 i 



Limestone 



fiom 

 Hedkarra. 



99. 064 



10.82 

 7.15 



36.61 

 6.86 

 1.25 



37.18 

 0.007 



99. 877 



The average chemical composition formed by the mixture of these 

 iron ores with the limestone, employed as flux, is as follows : 



Per cent. 



Silica (SiO:) 1 11.03 



Alumina (Al.Og) 2.50 



Lime (CaO) 7.51 



Magnesia (MgO) 2. 76 



Protoxide of manganese (MnO) .">. 615 



Protoxide of iron (FeO) 19.76 



Sesquioxide of iron (FejO;j) 43. 89 



Carbonic acid (CO,) 6.02 



Phosphoric acid (PjOs) 0. 013 



100. 013 



Such a charge yields, upon smelting, from 48 to 50 per cent, of pig- 

 iron, which is tapped direct from the blast furnace into the Bessemer 

 converters, and consists on the average of the following component 

 parts : 



Per cent. 



Carbon, combined (CC) 3. 460 



Carbon, graphitic (f;Gr) '/. 289 



Silicon (Si) 0.771 



Manganese (Mn) 4.491 



Phosphorus (P) •1.027 



Sulphur (S) trace. 



