216 ECONOMIC GEOLOGY 



Bessemer steel is made by burning out the impurities of the 

 iron by blowing air through the molten metal, then restoring 

 enough carbon to form steel. The impurities of the pig iron are 

 carbon resulting from the coke used as a fuel, silicon, sulphur 

 and phosphorus in the original ore. The pig iron is placed in a 

 pear-shaped converter lined with a basic brick, usually mag- 

 nesite, chromite or bauxite. At the bottom of the converter the 

 air is introduced from a compressor at a pressure of about 25 Ib. 

 per square inch. The air forces its way up through the molten 

 metal and oxidizes the impurities. Phosphorus, however, is not 

 removed by this process. Ferromanganese or spiegeleisen, alloys 

 containing a definite percentage of manganese, are then intro- 

 duced in a molten condition. Instantly all the oxygen in the 

 molten iron unites with the manganese while the carbon is taken 

 up by the iron, and Bessemer steel is the resulting product. 

 The steel is tough, elastic and widely utilized. 



Space might be given co the details of the manufacture of 

 foundry and forge iron, basic pig iron, charcoal iron, wrought 

 iron, spiegeleisen and ferromanganese; also open-hearth steel, 

 electro-metallurgy of iron and steel and a combination of the 

 electro-open-hearth and electro-Bessemer processes. These fields, 

 however, lie in the domain of metallurgy rather than in economic 

 geology. 



Uses of the Metal. The uses of iron are too well known to be 

 enumerated in detail. The larger uses fall into three distinct 

 fields. 1. Railroad construction. 2. Bridge architectural con- 

 struction. 3. The construction of vessels. 



While there are many crucible steel plants scattered through- 

 out the United States, Pittsburg and Syracuse are the only 

 cities possessing more than one such plant. The chief product of 

 the two crucible steel plants in Syracuse is high-grade tool steel 

 and used largely for twist drills, taps, dies, punches, and high- 

 speed steel which is standard not only throughout the United 

 States but the world as well. 



Another type of steel manufactured in Syracuse is magnet 

 steel which up to the beginning of the present century was largely 

 imported. This permanent magnet steel is largely used in elec- 

 trical measuring instruments, telephones and magnetos. 



The needle steel of Syracuse is widely used in domestic circles 

 but it is also sent to England and Germany. The razor steel is 

 sold in Solingen which is the cutlery center of Germany. The 



