jgg ON THE OXIDES OP IRON. 



carbon, or by that of heat and hidro^en : 3d, oxidation 

 by other metallic oxides : 4th, by water ; 5th, by ac)ds ; 

 siiid, 6th, by nitre. I shall examine the results obtained 

 by each of these methods separately. 



1st Method, Oxidation by air andjire, 

 Schseffer appears to be the first chemist, who observed. 



Simple calci- 

 Eafion by 



Gnyton, 



LaTt-)5/cr, 



D&xso, 



that iron increased in weight by ex}»osure to the air and 

 heat*. He remarked, that this increase, utter a complete 

 caVcinatiou, was one third the weight of the iron, conse- 

 q^uently 33*3 to 100 of metal. 



Guy ton repeated Schpcffer's experimentf . He found, 

 that iron filings calcined in a Hessian crucible, under the 

 muffle of an open furnace, increased ^f|-, or 27'4 to 100 

 of irop. J^teel filings, burned in the same manner, in- 

 creased 38'58 per cent. 



Lavoisier, calcining iron filings in the same vvay, ob- 

 tained four oxides, which had increased respectively 30, 32, 

 32*41, and 33 on the 100 of wonX. 



Mr. Darso calcined iron repeatedly, taking it out, and 

 triturating it in a mortar, after each time of exposing it to 

 the fire. By these means he obtained oxides, which in- 

 creased successively 20, 30, 3G, 40, 45, 50, and even 56 - 

 on 100 of iron filings^. 



I repeated with much care the experiment of Mr. 

 Darso, but could never obtain more than 42 on 100 of 

 iron filings without stirring them while calcining, and 45 

 with stirring themjj : which leads me to suspect some 

 errour in Mr. Darso's results. 



Bucholz calcined iron filings in a crucible, exposing 

 them to a red heat, and stirring constantly. The iron ac- 

 quired an increase of 24 to 100 of the metal. 

 an<l Lavoisier Lavoisier, repeating the experiment of Ingenhousz, who 

 again. burned fine iron wire in oxigen gas, burned iron turnings 



♦ Swec!ish Transactions, 1757. 



f Digression acad6mi:juc, Essai sur le Phloglstiqne, p. 8. 

 J M6m. de TAc. des Sciences, 1782, p. 525 andfol. 

 ^Journ. de Phys. 1806, torn. II, p. 294: or Journal, vol. XVII, p, 

 221, 267, 328. 



8 Ann. de Chim. toI, LXVII, p. G09 : or Journal, toI. XXVI, p. 



Ha5Fcnfrdtz, 



B«clio!z, 



147 



m 



