1840.] On Indian Iron and Steel. 191 



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» means the process of conversion is completed in a few liours, while 

 by the old method it was the work of from fourteen to twenty days. 



Now it appears to me that the Indian process combines the prin- 

 ciples of both the above described methods : on elevating the tem- 

 perature of the crucible containing pure iron and dry wood and green 

 'eaves, an abundant evolution of carburetted-hydrogen gas would take 

 place from the vegetable matter, and as its escape would be pro- 



j vented by the luting at the mouth of the crucible, it would be retain- 

 ed in contact with the iron, which, at a high temperature, appears 

 from Mr. Mackintosh's process to have a much greater affinity for 

 gaseous than for concrete carbon ; this would greatly shorten the 

 operation, and probably at a much lower temperature than were the 

 iron in contact with charcoal powder. In no other way can I ac- 

 count for the fact that iron is converted into cast-steel by the natives 

 of India in two hours and a half, with an application of heat, that, in 

 this country, would be considered quite inadequate to produce such 

 an effect, while at Sheffield it requires at least four hours to melt 

 blistered steel in wind furnaces of the best construction, although the 

 crucibles, in which the steel is melted, are at a white heat when the 

 metal is put into them, and in the Indian process, the crucibles are put 

 into the furnace quite cold. 



I do not believe that the Indian process exercises any influence 

 upon the quality of the steel ; its only advantage appears to be that 

 it enables the Hindti to accomplish an object with the very imperfect 

 means of applying heat within his reach, which it would be altogether 

 hopeless for him to attempt, were he to imitate the steps of the European 

 process. 



It seems probable that the selection of particular kinds of vege- 

 ■ table matter to afford carbon to the iron, may not be altogether a 

 'I matter of fancy. The Indian steel-maker of course knows nothing 

 i of the theory of his operations : he is satisfied with knowing that he 

 can convert iron into steel by fusing it with what he calls *' medicine," 

 and this medicine experience has taught him must be dried wood and 

 : green leaves ; and as different woods and leaves very probably contain 

 carburetted-hydrogen in very different proportions, experience may 

 have taught the Hindoo that he can make iron pass into the state 

 . of steel more quickly and with a smaller bulk of particular kinds 

 U ©f vegetable matter, than with others. The Cassia auriculata is the 

 ! only wood I have ever seen used for the purpose ; it contains a large 

 ! quantity of the extract called catechu : the leaf of the asclepias con- 

 r tains an acrid milky juice ; the leaf of the convolvulus is in no respect 

 I remarkable.— yowr/ia/ of the Royal Asiatic Society, vol. 5, p. 390-7. 



