38 Analysis of Iron Ore. 



by M. Proust, of" 148 for the maximum and 128 for the mi- 

 nimum of oxidation, the metal being represented by 100 : 



No. I.jNo.II.No.III. 

 Oxide of iron at the minimum 52*75 42*38 42*38 



Magnesia - - 5*00 14*00 13*60 



Water and carbonic acid - 42*25 43*62 43*22 



Silex - - - 00*00 00*00 00*80 



Total 100*00; 100-OOj 100*00 



Upon this hypothesis a quintal of the mineral No. I. 

 contains in metallic iron 41 per cent., No. II. 33 percent., 

 and No. III., calculated upon the same hypothesis, contains 

 33 per cent. 



This last result from No. I. agrees very well with that of 

 the experiment made at the forge of the laboratory of the 

 Council of Mines. As to the rest, I do not know if they 

 have been tried. 



(G) The celebrated Bergman, in a memoir entitled De 

 Mineris ferri albis *, announced that he found a very great 

 quantity of manganese in spathic iron. The authority of 

 the above chemist and of his followers was sufficient to in- 

 duce me to inquire if the oxide of this metal could not have 

 been kept in combination bv the oxide of iron. In order, 

 in the first place, to ascertain its existence, I melted the ore 

 by the blowpipe with glass of borax, as well in its natural 

 state as after being calcined, without obtaining, even with 

 the assistance of nitre, any colour which announced the 

 presence of manganese. I perceived, indeed, marks of this 

 metal on melting five grammes of each mineral with three 

 parts of caustic potash ; but the green tint which the alkali 

 took was very feeble ; it quickly disappeared, and the oxide 

 of manganese which I extracted was not appreciable in the 

 balance. 



It is probable, then, that Bergman mistook the magnesia 

 for the oxide >f manganese. We may even ascertain that 

 the presence of this metal in spathic iron is by no means 

 established by the facts quoted in his dissertation upon the 



* Opuscula Physica et Chemica, voLii. 



white 



