140 BULLETIN 4L', UNITED STATES NATIONAL MUSEUM. 



silicon and uningauese, and, wben made from imijure ores, phosphoi'as, 

 and sulphur, besides small amounts of other impurities. 



THE MANUFACTURE OF WROUGHT IRON. 



A small amount of wrought iron is manufactured direct from the ore, 

 mostly by the old Catalan process. In this process a rectangular forge 

 provided with suitable tuyeres is. charged alternately with fine ore and 

 charcoal. The charcoal reduces a i)ortion of the iron to tlie metallic 

 state in particles, and these particles stick to each other, and gather 

 into a lump, while the remainder of the iron with the impurities of the 

 ore form a slag, and settle to the bottom, from whence it is drawn off 

 by a suitable opening. When a sufficient amount of iron has accumu- 

 lated to form a "loupe' it is removed from the fire, and hammered down 

 to a bar, which is then ready for use. This process is very wasteful of 

 the iron, and is only practiced in remote regions except where, as in 

 Northern New York, a considerable amount of very pure ore is obtained 

 that can not readily be treated by any other process. The product 

 from these pure ores is very high grade. 



By far the largest amount of wrought iron is manufactured by the 

 puddling process. For this purpose the iron of the ores is first made 

 into pig iron in a blast furnace, and is then treated in a reverberatory 

 furnace to remove the impurities. The ])roduct of this operation 

 depends upon the quality of the ore used in the blast furnace, and the 

 care and skill of the workman in puddling. 



ROGERSFIELD MINE OF THE CHATEAUGAY ORE AND IRON COMPANY. 



This deposit, consisting of a mixture of magnetite, with feldspar, 

 hornblende, and quartz, is inclosed in gneiss. Its course is NE. by 

 SW., and has been traced for 12 miles. At a depth of 600 feet it is 

 18 feet wide. It is quite free from faults, although intercepted by trap 

 dikes. In mining, all the material between the vein walls is extracted, 

 leaving only sufticient pillars to support the roof, and the space left 

 empty, as shown on PL. xi. 



In 1884 15,000 tons of rich iurnace ore was extracted, of the follow- 

 ing composition : 



Per cent. 



Magnetic oxide of iron (Fe:i04) 70. 592 



Alumina (AlAO 1.^^83 



Lime (CaO) 4.260 



Magnesia (MgO) 2.112 



Maugaueao (Mn) traces 



Silica (SiO.) I'J. 2G0 



Phosphoric acid (PjO.,) 0. 031 



Snlphnr (S) 0.088 



Water (HjO) 1.080 



Also small quantities of carbonic acid, ;ilkalies, etc. 



Metallic iron (Fe) .'iLllS 



Phosphorus (P) 0.013 



Analysts. Booth, Garrett and Blair. 



