578 DISOXIDATIOIf or IRON BY HIDROQEN GAS. 



The oxidule of Cogne, treated with charcoal, in oti<5 

 cTperimeot yielded from 5 gr. [77*23 grs.) a button con- 

 taining 3-42 gr. [52*82 grs.] of iron, and 0*66 of a gr. 

 [10 19 grs.] of scoriae, which would make the loss about 

 27 to 100 of iron; and in another experiment the 5 gr. 

 yielded a button containing 3*38 gr, [52*21 grs.] of iron, 

 and 0-78 [12*05 grs.] of scoriae, making the loss 25 to 100 

 of iron. We will take the highest term, 27. 



The oligist iron of Elba yielded from 5 gram, a button 

 of iron weighing 3.6 [55*6 grs.] and 0*1 [1-54 gr.] of scoriae; 

 which would make the loss 30 to 100 of iron. 

 Iflfore loss in Thus the difference of loss in the two modes of reducing 



thertxJuction f^Q oxide of iron would be for the oxidule of iron of 



by hidrogen 



than in that by Cogne 46 by hidrogen, and 27 by charcoal ; and for the 



charcoal. oligist iron of Elba 54 by hidrogen and 30 by charcoal. 



Possible causes With regard to the causes, that may produce this dif- 

 ofthediffer- ference, we may dislinguish three: 1, the charcoal, that 

 combines with the iron, when the metal is fused with this 

 combustible: 2, the oxigen, that may remain combined 

 with the iron in the metallic button obtained : 3, the action 

 of the hidrogen on the iron, the gas dissolving and carry- 

 ing off some of the metal. 

 Addition to the Desirous of knowing what might be the influence of each 

 iron by carbon, ^^ these causes, I fused in a crucible lined with charcoal 

 5 gr. of iron wire preTiously soaked in oil, and obtained 

 a button weighing 5*13. Hence it follows, that somewhat 

 less than 0*03 of carbon was combined with it. 

 and by carbon I afterward dissolved 5 gr. of iron in nitric acid, in order 

 and oxigen. ^^ oxidate the metal to a maximum ; moistened the oxide 

 with oil; placed it in a crucible lined with charcoal to fuse 

 it; and obtained a button weighing 5*2 : consequently 0*04 

 of carbon and oxigen had combined with the iron. 



Supposing, that 0*04 of carbon and oxigen remained in 

 the buttons obtained from the oxidule of Cogne and the 

 oligist iron of Elba, it would follow, that the oxidule of 

 Cogne had lost near 32 per cent of oxigen, and the iron 

 of Elba near 36. 

 DifFerence be- These two results agree in placing the oxidule of Cogne 

 tween th« two ^^ ^^^ ^.^^j^ ^^ black oxides obtained by the decomposition 

 of water o^er iron 3 for this proportion of 32 Is nearly 



what 



