BAR MADE FROM CAST-IRON. 43 



ore, when reduced, is transferred to and worked in puddling- 

 furnaces. If steel be the object, the iron is suifered to remain 

 in the retorts a longer time. Although there is every reason 

 to believe that both bar-iron, steel, and cast-iron can be made 

 in this manner, yet we may doubt the economical value of the 

 project, except on a limited scale, for special purposes, and 

 with the best ores. Iron must still be made by the older pro- 

 cesses from poorer ores, which are much more abundant than 

 the richer. For details of the patent, see Journ. Fr. Instit. 

 (3) XX. 65. 



Cast changed to Bar-iron. — Stirling's processes for the con- 

 version of cast into bar-iron are deserving of consideration. 

 To a given weight of cast-iron, about 20 to ! as much scrap- 

 iron is added, most conveniently by putting the scrap-iron into 

 the hollows, which it is designed to fill by cast-iron run di- 

 rectly from a blast-furnace. The pigs are then puddled as 

 usual, taking care that the whole be thoroughly melted. The 

 stream of cast-iron may also be run upon the hearth of a re- 

 verberatory, containing scrap-iron, heated to a point below 

 welding ; the heat is raised until both are incorporated, and 

 the metal is then run into a puddling-furnace. With better 

 qualities of cast-iron, from j'q to ^ of scrap-iron may be used. 

 In order to obtain a malleable iron, harder, less fibrous, and 

 more granular than usual, | or 1 per cent, of tin is added to 

 the malleable iron mixtures above described. Bismuth, an- 

 timony, and arsenic will produce a similar effect. Such hard 

 iron is said to work well, while hot, under the hammer, in the 

 squeezer, between the rolls, and in the smithy. Zinc may be 

 employed in the form of calamine. About the same quantity 

 of copper also gives additional hardness to iron. Black oxide 

 of manganese, in the proportion of J to 1 per cent, of the 

 mixed malleable iron, gives a more steely character to it, 

 hardening the iron and facilitating the puddling process. (Rep. 

 Pat. Inv. July, 1850.) 



Bar madefrojii Cast-iron. — Prof. Miller's (Ch. Gaz. vi.) ana- 

 lyses show that iron made by cementation contains more 

 carbon than good bar-iron, but much less than it did before 



