OF ARTS AND SCIENCES. 343 



billing with this clement, the heat disengaged is ample for carrying 

 the temperature of the mass still higher. A portion of oxide of iron 

 being formed, the mechanical motion imparted by the jets of air 

 favors the contact of the oxide with the carbon, 2chich then hums with 

 the condensed oxygen of the oxide of iron. The products of this 

 combustion, arising from the mingling of oxide of iron and graphitic 

 carbon and pure graphite, are two, — pure iron, and carbonic oxide ; 

 the former uniting with the mass, the latter escaping as gas, and burn- 

 ing in the atmosphere, or even with any oxide of iron it meets with 

 in the mass. A moment's consideration of the operation shows that 

 the combustion of the iron at the first stage leads to the separa- 

 tion of the carbon as carbonic oxide, and a reduction of the oxide 

 formed to pure iron. Silicium, phosphorus, cyanogen, and sulphur, 

 the bases of the alkaline earths, and interposed slags are oxidized and 

 removed as fusible compounds in the same way, lohile the pure iron 

 assiiraes the crystallized state. The combustion of the iron raises the 

 temperature of the acting bodies far above the initial point, while the 

 reduction of the oxide of iron formed diminishes in a corresponding 

 degree this temperature. Were the conditions of the experiment 

 such that the oxide formed from the iron burned was equivalent to 

 converting the carbon into carbonic oxide only, at the moment the 

 oxide of iron became pure iron, then no increase of temperature 

 would be noted, and the cooling influences of the surrounding medium 

 would cool the acting bodies below the initial temperature. Hence, 

 it is essential that more than an equivalent of iron should be burned, 

 and a loss of this substance must take place, so that the operation of 

 purification by the new process is carried on by substituting iron as 

 fuel for carbon consumed in the ordinary process. Assuming six pounds 

 of carbon to exist in a sample of crude iron containing ninety-two 

 pounds of pure iron in one hundred pounds, then tioenty-eight pounds 

 of iron must be burned to oxide, and the six pounds of carbon will 

 exactly reproduce the twenty-eight pounds of iron, leaving ninety-four 

 parts of iron deprived of carbon. But the practical result differs 

 from this statement, inasmuch as a positive loss of at least ten pounds 

 of iron occurs ; and in explaining the increased elevation of tempera- 

 ture, we neglect that portion of the iron which, having been burned 

 and again reduced, adds to the mass, and keep in view the effect of 

 the combustion of ten pounds of iron lost in the operation at the high 

 temperature attained. Accurately, some addition to the temperature 



