On the Component Parts of ' Iroi-ftutits . 247 



of iron and (tee 1 , fhall be fully confidercd in connection with 

 this curious mode of manufacturing thefe ftates of the metal 

 from ores without fufion^ which, from its novelty and (im- 

 plicity, deferves a thorough investigation of operation and 

 principle. 



De-oxygenation (imply confifts in expofing iron-ftone or 

 ore, ftratified with coaly nutter, fuch as the duft of pit-coal 

 coaks, or the charcoal of wood uncxpofed to air, at a high 

 temperature. The oxygen contained in the ore is taken up 

 by the charcoal, and palled off in the ftate of carbonic acid ; 

 while the water, carbonic acid, &c. previoufly existing in 

 the (tone, is evaporated by the addition of caloric. In pro- 

 portion as the ore becomes cleared from thefe mixtures, the 

 metal becomes more and more revived, approaching how- 

 ever to the ftate of malleable iron, though ftill interfperfed 

 with the original quantity of earthy parts united in the 

 (tone. By increafing the temperature, and continuing its 

 duration, the particles of iron unite, and form themfelves 

 into fibres, which, even when cold, maybe twifted and bent 

 a little ; ftill however having the original quantity of earthy 

 matter almoft invifibly interpofed betwixt their interftices. 

 If the heat is urged ftill further, the iron, now malleable, 

 begins to take up a portion of the carbon from the charcoal, 

 and the metal then commences its change to fteel. 



During any part of the procefs, mould air come in contact 

 with the ore, by previoufly deftroying thefurrounding char- 

 coal, an immediate oxydation of the iron takes effect, pro- 

 portioned in its increafe of weight to the ftagc of the ope- 

 ration at which it is effected. The ore has then paffed into a 

 friable, bulky, and unmetallic ftate. 



In de-oxygenatingiron-ftones, with an intention of difco- 

 vering and of eftablifhing an analogy as to the quantity of 

 oxygen contained in the reipective claffes of (tones, I was fre- 

 quently led to conclude, that argillaceous and calcareous 

 iron-ftones contained lefs oxygen than iron-llones where a 



R 4 greater 



