m 



and Fourcroy 



Remarks on 

 these experi- 

 sentSk 



Attempts with 

 substances 

 containing 

 carbon, by 



with charcoal, 

 by Hassen- 

 f;atz J 



VH THE OXIDES OF IKiXSti 



k can be ascribed to oxlgen di»engtiged from the iroti} 

 would be about 6 per cent. „ .,oS 



Fourcroy, calcining i44 grains of oxide of irow.i)lS<([ 

 porcelain crucible hermetically closed, found that the ap- 

 paratus had lost 60't) grains, though the lute was fustd, 

 aud the lid united to the crucible by an earthen glass. 



These different results in experiments, that may be con- 

 sidered as similar, leave some doubts on the conclusions, 

 that Bucholz draws from his. In fact, the crucibles h« 

 employed were vitrified ; which shows, that they had 

 been exposed to a higher temperature than Ithat in 

 which they were made. This increased temperature of 

 the crucibles therefore leaves the cause of the loss of 

 weight, which the crucible and oxide had undergone, a 

 matter of doubt. It may as well be ascribed to water re- 

 maining in the earth of the crucible, as to oxigen disen« 

 gaged from the iron. 



Bucholz also endeavoured to diminish the oxigen in the 

 oxide of iron by triturating and heating it with substances 

 containing carbon ; for instance, carbonate of ammonia, 

 supertartrite of potash, wax, lampblack, and succinate of 

 ammonia. With the first three the oxide experienced only 

 an imperceptible diminution and reduction ; and with the 

 others the diminutions tvere very variable. With the lamp- 

 black one portion of the oxide had undergone no change, 

 while another was reduced to the metallic state. 



The oxide and oxidule of iron may be completely, dls- 

 oxidated and reduced by heating or fusing them with sub- 

 stances containing carbon and hidrogen. 



At Moustier we fused with charcoal a variety of oxidn- 

 lated iron in dodecaedral crystals from a mine in the valley 

 of Aost. This ore, which contained 0*98 of oxidule and 

 0'02 of silex, yielded a button weighing 76. If no silex 

 had been present it would have weighed 0*775. Supposing 

 the metal to have retained 0*005 of carbon, it would follow, 

 that this oxidule contained 30 of oxigen to 130 of iron. 

 Two oxidules from the isle of Elba, one assayed at the 

 laboratory of the Practical School of Mining, the other at 

 the laboratory of the Council of Mines, registered No. 

 263, yielded 0*72 of iron. The first contained 0*05 of 



foreign 



