70 JOHN BIRKINBINE 



charcoal; these smelt brown hematite and some carbonate 



ores. 



In addition to the brown hematite ores mentioned as 

 occurring in southwestern Massachusetts and northwestern 

 Connecticut, bog ores are found in eastern Massachusetts, and 

 were the foundation upon which the first practical develop- 

 ment of the iron industry in the United States was based. 

 Magnetic ore occurs in Rhode Island, and magnetites and 

 brown hematites have been mined in Maine and Vermont. 



The magnetite ores extending from New York across 

 northern New Jersey into Pennsylvania, have been liberally 

 developed in a number of locations in New Jersey. The im- 

 portance of the industry, however, has declined in late years, 

 the bulk of the product being confined to a few of the more 

 important mines. As a rule, the ores of New Jersey are lean, 

 and some of them carry sulphur or phosphorus in excess, but 

 others are of Bessemer grade. 



Pennsylvania, although not the pioneer in American iron 

 industry (its initial enterprise having been established about 

 1716), rapidly advanced to first place, and by reason of the 

 wide distribution of all classes of iron ore and abundance of 

 fuel, became the largest producer of iron, and still holds that 

 rank, although the bulk of the iron ore used in the manufac- 

 ture of its iron and steel products is mined outside of the state. 



The most important iron mining operation in Pennsyl- 

 vania is that carried on in the Cornwall ore deposit in Lebanon 

 county, which has produced about three fourths of a million 

 tons annually, and, since the year 1740, has contributed a 

 total approximating eighteen million tons to supply Pennsyl- 

 vania iron works. This ore as mined yields on the average 

 about 46 per cent of iron, carries about three fourths of 1 per 

 per cent of copper, and about 2| per cent of sulphur. It must, 

 therefore, be roasted, and ore roasting kilns have here ob- 

 tained their largest development. Furnaces of the Gjers 

 cylindrical form, using solid fuel, are used at some plants, and 

 at others there are circular or rectangular kilns heated by pro- 

 ducer gas after the Davis-Colby patents. 



The Cornwall ore bank, at Cornwall, Lebanon county, is 

 a large deposit of magnetite from which immense quantities 



