fi68 



ON THE OZI9E8 OF IRON. 



M 



29 in. [99*8], which would make the quantity of oxigea 

 combined with 100 of iron 2f)*. 



Vanquehn, having dissolved several kinds of steel in di- 

 lute sulphuric acid, oV^tained from 108 to 121 cubic inches 

 of hidroi^en gas ; whence the quantity ofoxigen combined 

 with 100 of iron would be from ^266 to 29*9 f. 



f^Vom the products of hldrogen gas obtained by dissolving 

 iron in dilute sulphuric acid we must exclude those of 

 Bergman, which exhibit too great differences to deserve any 

 contidence ; and that of Priestley, which appears much too 

 considerable not to induce the suspicion of some errour, or 

 that great part of the iron was oxided at a maximum :^. 



The other exxjeriments lead to the conclusion, that the 

 quantity of oxigen combined with iron varies between 2(>'(5 

 and 29*9 to 100 of the metal dissolved. 



Iron is seldom pure, always containing carbon, scoriae, and 

 sometimes oxiciule. The iron that gave Vuuquelin 121 cubic 

 inches of hidrogen contained 0*00633 of carbon, and 

 0*00626 of siliceous earth. 



The impurity of iron leads to the presumption, that the 

 quantities of hidrogen obtained were less than would have 

 been produced, if the metal had been perfectly pure; whence 

 we may consider the greatest quantity of hidrogen obtained 

 as resulting from the purest iron: and that analysed byV^au- 

 quelin contained at least 0*01 of foreign matter, so that we 

 may carry the proportion of oxigen combined with 100 of 

 iron dissolved in dilute sulphuric acid as far as 30 without 

 danger. But, according to Thenard, the iron in this solu- 

 tion is in the state of white oxide ; whence the white oxide 

 must contain 30 of oxigen to 160 of metal, or consist of 77 

 parts iron and 23 oxigen. 



Of the quantity of oxigen combined with iron ascertained by 

 the oxides contained in the solvtions, 

 Calculation of "^^^^ quantity of oxigen contained in tlie oxides separated 

 tse quantity from their solutions may be ascertained in three different 



Vauquelin. 



Experiments 

 to be exclu- 

 ded. 



Conclusion 



froni the 

 Others. 



But iron is sel- 

 dom p lire 



so that we may 



estimate the 

 oxi^n at the 

 A^ghest. 



Thenard's 

 white o^rtde. 



• Miem. de r Ac. des Sciences, 1786, p. 1 66 and following, 

 f Journ. des Mines, No. 25, p. 29. 



X Jf my conjecture, expresse*|l in a preceding ncte, be right, this ro- 

 mark on Priestley's experiment Is unnecessary. C. 



modes 



