IRON ORES. 257 



different stages of the process. The ore after a pievious roasting in a 

 kiln, is pounded up and sifted ; the coarser part is piled up in the forge 

 on the side opposite the blast, and charcoal fills up the rest of the space. 

 After the heat is well up, the finer siftings are thrown at intervals upon 

 the charcoal fire. The basin below, which has been previously lined 

 with two or three coats of pounded charcoal, or loam "and charcoal, re- 

 ceives the iron as it is reduced and runs down. The slag is occasionally 

 removed from the surface of the basin through holes opened for the 

 purpose. The iron, when sufficiently accumulated, is taken out in a 

 pasty state and at once forged. The process usually lasts five or six 

 hours. A lump or bloom of malleable iron is thus produced in three or 

 four hours. This cheap and simple process has long been used in Cat 

 alonia, and it is hence called the method of the Catalan forge. By a 

 slow operation, and but a small quantity of siftings, worked with an 

 upraised twier, the proportion of steel obtained by the process is in- 

 creased. This mode of reduction is adapted only for the purer and 

 more fusible ores ; and moreover it requires a large consumption of fuel 

 and is attended by a considerable loss. The argillaceous ore of the coal 

 region would yield only an iron glass in a Catalan forge. 



By another mode of reduction, the iron ore coarsely powdered ia 

 mixed with coal in certain proportions, or a material containing the 

 requisite amount of carbon, and the charge is heated in a reverberatory 

 furnace till reduction has taken place. The carbon carries off the 

 oxygen of the ore, and if the proper proportions have been employed, it 

 leaves a mass of malleable iron behind. 



Steel. . Wrought iron is changed to steel by a process called cemen- 

 tation. The best iron is heated with charcoal ; a portion of carbon is 

 thus absorbed, and the iron at the same time acquires a blistered sur- 

 face, and becomes fine grained and fusible. When the blistered steel 

 is drawn down into smaller bars and beaten, it forms tilted steel; and 

 this broken up, heated, welded, and again drawn out into bars, forms 

 shear steel. Cast steel is prepared by fusing blistered steel with a flux 

 and casting it into ingots, and then by gentle heating and careful ham- 

 mering or rolling, giving it the form of bars. 



Steel is also formed direct from certain ores of iron, more particularly 

 when oxyd of manganese is associated with them, and especially from 

 the spathic iron, which often contains a portion of carbonate of manga- 

 nese. The oxygen of the manganese is said to remove part of the car- 

 bon from the cast iron, and thus reduce it to the state of steel. There 

 are 1 or 2 per cent, of manganese in the metal thus obtained. The 

 product is of inferior quality as steel, but is largely manufactured in 

 Germany. The wootz of India is a steel obtained from a black ore of 

 iron, in a furnace even simpler than the Catalan forge. It is said to 

 contain a minute proportion of silicium and aluminium. 



The amount of iron manufactured in the United States in 1853, (over 



a third in Pennsylvania,) was 1,000,000 tuns ; in Great Britain, in 1852, 



,700,000 tuns; in France, in 1849, 514,000; in Russia, in 1845, 



400,000 ; in Sweden, in 1846, 145,000 ; other parts of Europe, (Aus 



tria, Belgium, Germany,) 700,000 tons. 



How is steel made ? Describe the kinds of steel. How is steel inadu 

 direct from ores of iron ] 



