iitSoitiiil'tbk OP IROJ^ BY rilDkOGEI* (JAi. 3tl 



Finally, at my departure from Moutiers, I reqbestetl the 

 pupil Desroches to make fresh experiments oti the decom- 

 position of the oxidule of iron of Cogne, and oligist Iroa 

 of Elba. The official statement of these experiments, cer- 

 iified hy engineer Leboullenger, I shall proceed to lay be- 

 fore thii publifc. 



sExperitnents on the Disoxidation of Oxide and Oxidule 

 of Iron* 



li has befcn said, thit all metals are capable of being dis- Disoxidation ai 

 oxidated by heat, and that the temperature required fo^ metals by heat. 

 their reduction is much higher than that of their oxidation. 

 It is easy to conceire, that, if the tefldency to take the 

 aeriform state be less powerful than the attraction of the 

 oxigen by the metal, the oxigcn will be solidified, and an 

 oxide formed: but if the elasticity be superiot to the at- 

 traction, no combination, or oxidation, will take place. 

 This occurs in the manufacture of minium: too strong a 

 fire produces massicot, and sometimes reduces the oxide en- 

 tirely. It is observable too, that, beyond a certain tetn- Oxidation by 

 perature, the time Required for oxidation is in the inyerse^^^** 

 ratio of the heat. This I had an opportuity of observing 

 in the oxidation of iron by heat last year. Having taken 

 some pure filings of good iron, and exposed them to a 

 graduated heat, I obtained in a very little time an addition 

 of 32 per cent : I increased the heat and the current of 

 air, but it was a long while before I gained 40 per cent: 

 and it was not without a great deal of trouble, and a ver^ 

 long time, that t obtained the known result of 45 per cent, 

 which I could not exceed. 



But is heat alone capable of reducing all metals ? This Are all metalj 

 question is already decided with respect to some, which [^^"J^,^^^® ^y 

 have but a feeble attraction for oxigen. As to those which 

 retain it forcibly, it may be, that the heat requisite for their 

 disoxidation is superior, or at least equal to that necessary 

 for their fusion ; and then it would be impossible to separate 

 ihe gas from the riietal. 



But if a powerful disoxidizer be employed ifi conjunction 

 with caloric, so great a heat will not be required to reduce 

 the metal: thl3 no doubt induced tlt^ ;^oaDger Mr. Ber« 

 ^"^"''"i Bb2 . thollet 



