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Scientific Intelligence. 



going on within the vessel, the metal being tossed violently about and 

 dashed from side to side, shaking the vessel by the force with which it 

 moves, from the throat of the converting vessel. Flame will then imme- 

 diately issue, accompanied by a few bright sparks. This state of things 

 will continue for about fifteen or twenty minutes, during which time the 

 oxygen in the atmospheric air combines with the carbon contained in the 

 iron, producing carbonic acid gas, and at the same time evolving a pow- 

 erful heat. 



Now, as this heat is generated in the interior of, and is diffusive in in- 

 numerable fiery bubbles through the whole fluid mass, the metal absorbs 

 the greater part of it, and its temperature becomes immensely increased, 

 and by the expiration of the fifteen or twenty minutes before-named, that 

 part of the carbon which appears mechanically mixed and diffused 

 through the crude iron has been entirely consumed. The temperature, 

 however, is so high that the chemically combined carbon now begins to 

 separate from the metal, as is at once indicated by an immense increase 

 in the volume of flame rushing out of the throat of the vessel. The 

 metal in the vessel now rises several inches above its natural level, and a 

 light frothy slag makes its appearance, and is thrown out in large foam- 

 like masses. This violent eruption of cinder generally lasts about five 

 or six minute's, all further appearance of it ceases, when a steady and 

 powerful flame replaces the shower of sparks and cinder which always 

 accompanies the boil. 



The rapid union of carbon and oxygen which thus takes place adds 

 still further to the temperature of the metal, while the diminished quan- 

 tity of carbon present allows a part of the oxygen to combine with the 

 iron, which undergoes combustion and is converted into an oxyd. At 

 the excessive temperature that the metal has now acquired, the oxyd as 

 soon as forrueci undergoes fusion, and forms a powerful solvent of those 

 earthy bases that are associated with the iron. The violent ebullition 

 which is going on mixes most intimately the scoria and the metal, every 

 part of which is thus brought in contact with the fluid oxyd, which will 

 thus wash and cleanse the metal most thoroughly from the silica and 

 other earthy bases which are combined with crude iron, while the sulphur 

 and other volatile matters which cling so tenaciously to iron at ordinary 

 temperatures, are driven off, the sulphur combining with the oxygen and 

 forming sulphurous acid gas. 



The loss in weight of crude iron, during its conversion into an ingot 

 of malleable iron, was found on a mean of four experiments to be 12-J- 

 per cent, to which will have to be added the loss of metal in the finish- 

 ing rolls. This will make the entire loss probably not less than 18 per 

 cent, instead of about 28 per cent., which is the loss on the present sys- 

 tem. A large portion of this metal, however, is recoverable by treating 

 with carbonaceous gases the rich oxyd thrown out of the furnace during 

 the boil. These slags are found to contain innumerable small grains of 

 metallic iron, which are mechanically held in suspension in the slags, and 

 may be easily recovered. I have before mentioned that after the boil 

 has taken place a steady and powerful flame succeeds, which continues 

 without any change for about ten minutes, when it rapidly falls off. 



As soon as this diminution of flame is apparent, the workman well 

 know that the process is completed, and that the crude iron has been 



