

different Earths for Carbon.- ss* 



place -when nearly 3-4 ths of the vyhole metal is revived, and 

 decidedly proves a reverse of affinity to what at first existed. 



At the beginning of the experiment we find that the char- 

 poal prefers uniting with the general body of oxygen, rather 

 than clearing a minute portion and reviving its appropriate 

 metal. This takes place till a considerable part of the oxy^ 

 gen is dissipated.. In the progress of this, the affinity be- 

 twixt the carbon and iron is gradually developed ; and be 7 

 fore it is fully established a portion pf the iron is precipitated 

 in a malleable state, not as a direct consequence of the union 

 pf the carbon with it, but in consequence of the oxygen of 

 the oxide being removed, and the particles left in a metallic 

 state. So long as this takes place, I look upon the affinities 

 of carbon for tjie remaining oxygen of the ore, and for its 

 metallic contents, as nearly balanced ; and this will always 

 have a direct reference to the proportion of each. When this 

 .equilibrium is destroyed by the addition qf certain extra 

 portions of carbon, a paramount affinity is immediately esta- 

 blished betwixt these and the iron which had before been 

 separated in the malleable state, and steel or crude iron of 

 various degrees of saturation proportioned to the carbon is 

 the result. 



From another mode of operatiqn it is pretty evident that 

 this reverse of affinity is occasioned in a great measure by 

 the temperature, particularly as in the above case, where it 

 uniformly is productive of fusion. If the same oxide here 

 operated upon, or indeed any ore, is exposed to a tem- 

 perature in contact with charcoal considerably short of 

 fusion, a deoxidation nearly complete will take place, pro- 

 vided the experiment as to proportion of mixture and time 

 has been properly conducted, The matter thus exposed will 

 be found to have lost considerably in weight by the Joss of 

 oxygen. If it is carefully freed from the surrounding char- 

 coal, washed, and immediately dried and introduced into a 

 clay crucible and exposed to a very high heat, a'button of 

 metal will be found, amounting to 8-10ths or D-10ths, the 

 whole produce in iron which the ore contained. This iron will 

 be in the state of malleability nearly as soft as copper when 

 cold, but uncommonly red-short when heated beyond a 

 bright red. The deficient iron, amounting to 1 or 2-l0ths, 

 will be found in a small portion of glass of iron attached tu 

 the edges qf the button, and which may be easily called to 

 existence by the addition of a few grains of carbon. 



This still proves that the temperature employed in ce- 

 mentation, though adequate to remove the greatest part of 

 {he oxygen, yet is insufficient to dissipate ifs last remains. 



U 3 



