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ganese takes the place of carbon, and this alloy does not take 

 up carbon. One deposit of manganesian iron ore, in New Jersey, 

 at Andover, furnishes iron containing nine per cent, of man- 

 ganese. It is too brittle for most castings, but is the best iron 

 for making steel. In reducing it to bar iron, it " comes to 

 nature " with very great rapidity. Carbonaceous irons are very 

 slow in " coming to nature," but by being mixed with this iron 

 they become quite tractable, producing a remarkably tough iron. 

 Dr. Jackson's theory of the action of oxide of zinc in iron, was, 

 that the oxygen of the oxide of zinc in the Franklinite com- 

 bines with the sulphur of the bad iron, producing sulphurous 

 acid, which goes off by heat and the zinc is then sublimed 

 and leaves the iron. In the manufacture of the white oxide of 

 zinc, from the New Jersey mineral, there is an immense residue 

 of Franklinite, which at least pays for the fuel consumed in the 

 process. Some zinc remains combined with the Franklinite, but 

 in the high temperature of a reverberatory furnace this comes 

 off as a pale yellow oxide, so colored partly by being vitrified, 

 and partly by a portion of iron and manganese. This makes a 

 very valuable paint for railroad cars, &c. Five tons of the 

 white oxide of zinc are now manufactured daily from this 

 mineral at one manufactory. 



Mr. D. A. Welles inquired if Prof. Rogers was in pos- 

 session of any information relative to the manufacture of 

 Sheet Iron in the United States. 



Prof. Rogers said, he knew of one establishment for its 

 manufacture, but was not entirely conversant with all the 

 processes. The iron made was neariy as good as the Rus- 

 sian, and its excellence was due, he thought, mainly to the 

 great care taken to keep up a given temperature during the 

 rolling process. 



Mr. Welles said, that some time since, Dr. Hayes and 

 himself had made an examination of the Russian iron to 

 discover, if possible, the secret of its excellence, about 

 which so much mystery had been kept up. They had 

 come to the conclusion that it was due only to the very 

 great purity of the iron. The lustre on the surface was 



