-50 ANNUAL OF SCIENTIFIC DISCOVERY. 



rus, -37 ; manganese. '85, with traces of titanium and tin. The Swedish 

 gun metal has great resemblance to the Russian. The French gun metal 

 was from the cannon foundry at Rouelle ; the Belgian from the Government 

 foundrj'. The result of the analysis shows thus much as certain, that iron 

 smelted with mineral fuel may be obtained in abundance in Great Britain, 

 containing not more phosphorus or sulphur than is usually found in charcoal 

 iron ; and proofs exist of the ease with which silicium may be removed from 

 pig iron ; and it may therefore be confidently expected " that we are not 

 dependent on a supply of charcoal iron for the production of durable guns" 

 although it may be at present premature to compare from analysis the merits 

 of charcoal iron with the better qualities of British cold-blast iron as materials 

 for ordnance. 



IMPROVEMENTS IN THE MANUFACTURE OF IRON. 



No one invention or discovery of the past year has excited more general 

 interest and attention, than the improvements in the manufacture of iron, first 

 publicly announced at the meeting of the British Association by Mr. Bessemer,* 

 of England. The readers of the Annual of Scientific Discovery will doubt- 

 less recall the fact, that the name of Mr. Bessemer has for a series of years 

 been associated with some of the most important English patents noticed in 

 the successive volumes of this work. He appears to be an inventor by pro- 

 fession, and to a considerable extent successful in his various undertakings. 

 The present invention was at first received with a general enthusiasm then 

 doubted, denied, and condemned. Nevertheless, the invention stands; is 

 capable of performing all that has been claimed of it ; and, theoretically at 

 least, is a great advance in the manufacture of iron. We have seen and 

 examined specimens of the iron produced and used by Mr. Bessemer, hi 

 every stage of the process, and the evidence they present is clear and con- 

 vincing. Notwithstanding these remarks, we would also assert that the pro- 

 cess of Mr. Bessemer is no improvement over the processes now used in 

 several of the iron furnaces in the United States. The process of converting 

 pig or cast iron into wrought iron, consists essentially in burning out or elimi- 

 nating an excess of carbon existing in the cast iron. In the ordinary puddling 

 furnaces, the pig iron is melted and the oxygen gradually burned out by cur- 

 rents of air blown over the surface, and constantly stirring and working. Mr. 

 Bessemer effects the same end by forcing ah- under powerful pressure into the 

 melted mass of pig iron from below. The fused metal under this action is 

 thrown into violent agitation, boiling and frothing, until nearly every particle 

 has been subjected to the influence of the ah" current. Oxide of iron is first 

 formed, which, imparting a portion of its oxygen to the carbon, sets free the 

 latter body in the form of carbonic acid. A portion of the carbon is also 

 undoubtedly acted upon directly by the oxygen of the air. The oxide of 

 iron formed also acts as a flux, in separating the silica and other impurities 

 contained in the pig metal. The result of this operation is a direct loss of 

 from 20 to 30 per cent, of metal, principally due to the formation of the oxide 

 of iron. The mass, as it comes from the vessel in which it has been acted upon, 

 is spongy and highly vesicular, resembling scorias. Subjected to the action of 



