On iha Component Ptzrls of Iron-jhms. 253 



This iron-ftone was frittered, very magnetic, but diffolved 



lefs rapidly in acids, and with lefs eftervefcence ; colour of 



the fra&ure light grey, and (lightly fpongy. The practical 



analysis of this filiceous iron-ftone will therefore fund thus : 



Carbonated crude iron obtained in the affay 

 furnace - - - - - 36 parts, 



Water, acid, and a confiderable portion of 

 fulphur - 28-6 



Oxygen taken up as above - 14*8 



Further, as will hereafter be (hewn 

 in making the iron-ftone pafs into a 

 ftate of malleability - - 2*5 — 17-3 



Earths, viz. filex 9, lime 6, clay 3*1, = - 18*1 



100 parts. 



In thefe experiments I wiihed to obtain refults which 

 would throw light upon the de-oxygenation of iron-ftones., 

 with a view to applv them to practice upon an extended fcale. 

 I therefore ufed frcfli ore, in order to prefent nearly the fame 

 furface to the acYion of the heat, and to be able to judge of 

 the refults apart from each other. In torrefa&ion it fre- 

 quently happens that the ftone is reduced too fmall to enable 

 us, by its fubfequent treatment, to form a probable opinion of 

 the tenacity, or otherwifc, with which iron-ftones hold their 

 oxygen. The difference betwixt returning into the crucible 

 the fame pieces deprived of their volatile mixtures, and ope- 

 rating upon frefli ore, cannot be great, efpecially when they 

 are fele6ted from fragments of the fame mafs, directed by 

 an intimate acquaintance and thorough knowledge of the 

 qualities indicated by their external forms. 



All iron-ftones thus expofcd to de-oxygenation become 

 more or lefs faturated with carbon ; it forms a union like 

 carbon in fteel, and its prefence is only afcertained when the 

 iron-ftone is ditlolved in an acid, by riling to the top, and 

 forming a fine pellicle pofleffing luftre and various fhades 



of 



