202 ANNUAL OF SCIENTIFIC DISCOVERY. 



furnace, for a period of time varying from six to ten days, finally allowing 

 them to cool slowly. In this case, the character of the iron is changed, by a 

 removal of a part of its carbon, through the agency of the oxygen of the 

 powdered hematite. An improvement on this process, recently devised by 

 Prof. A. K. Eaton, consists in the substitution of the oxide of a volatile 

 metal, as zinc, instead of that of iron; the volatile metal going off in vapor 

 as it parts with its oxygen to the carbon of the iron, and thus affording 

 room for fresh portions of oxide to fall in and continue the process. The 

 metallic vapor is at the same time received in a condensing vessel, and is 

 afterward cast into ingots. 



According to the New York Tribune, the same inventor has devised a sim- 

 ilar method applicable to the production of steel, which, indeed, may be 

 produced in the process described; steel being, in fact, but a partially 

 decarbonized cast iron, and, therefore, actually resulting in one stage of the 

 conversion of cast into malleable iron. 



Prof. Eaton, however (according to the above authority), has found that 

 the hydrates and carbonates of the alkalies, heated in contact with cast iron, 

 exert a decarbonizing action like that of oxide of zinc. Selecting carbonate 

 of soda, a compound of carbonic acid and oxide of sodium, and causing 

 this to fuse and cover bits of cast iron, the salt is decomposed, the oxide of 

 sodium giving up its oxygen, which unites with the carbon of the iron, 

 forming carbonic oxide, which escapes, together with the carbonic acid of 

 the salt. Metallic sodium is vaporized in meeting the oxygen of the air, 

 admitted in limited quantity into the retort for this purpose, and is recon- 

 verted into soda. The liquid solution reaches every portion of the surface 

 of the cast iron, and the chemical action gradually penetrates the whole 

 mass. The affinity of the sodium for sulphur and phosphorus causes them 

 to be seized and withdrawn from the iron, and they both are retained by 

 the alkali in the condition of sulphuret and phosphuret of sodium. At the 

 same time silicon is also separated, through its affinity for oxygen, with 

 which it forms silicic acid, and this unites with the soda, forming silicate of 

 soda. The experiments so far made are highly encouraging, that this will 

 prove not only an efficient method in practical operations upon a large scale 

 of removing these elements so injurious to iron, but that, in consequence of 

 this property, the vast bodies of sulphurous iron ores, which, though rich in 

 metal, have so far defied the skill of metallurgists to effect with economy 

 their reduction to good iron, may now be rendered of practical importance. 

 The experiments have been made upon a scale which might answer for 

 manufacturing operations; a product of several hundred pounds of steel 

 having been obtained, which has been cast into ingots, hammered into bars, 

 and made into a variety of small articles. 



The expense of the manufacture is comparatively light. In the first place, 

 the raw material employed is the cheap cast iron, which never before was 

 considered applicable to this use. The process is rapid, and no excessive 

 heat is required, like that for melting and carbonizing malleable iron, as 

 practised in one method of making steel, a method which involves the use 

 and rapid consumption of highly expensive crucibles. A red heat sufficient 

 to fuse the soda is all that is necessary. Crude carbonate of soda, or soda 

 ash, suitable for this use, is a cheap product, especially considering that the 

 same bath of it can be used repeatedly, and when it becomes too impure, it 

 can be restored by inexpensive methods to its former condition; though 

 seme more useful application for the metallic sodium may render this inex- 



