PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 455 



Mr. Chnrchill. — The burning of the zinc would give more 

 heat than carbon. 



Col. Curtis. — In my judgment the iron trade of this company, 

 if properly developed, could be made equal to the whole cotton 

 crop of the south. We now import about fifty millions of iron 

 and steel, and are draining California of its gold to pay for it, 

 while we ought to be able to export those metallic substances. 



Mr. Fisher, — Will Bessemer's process operate favorably with 

 the Franklinite ore ? 



Mr. Selleck. — It is utterly impossible to make iron from the 

 Franklinite ore, unless you mix an oxide of iron with it. It is 

 made into steel. 



Mr. Tillman. — It is the Kelly process, and not the Bessemer 

 process, for Mr. Kelly used it in this country long before Besse- 

 mer. The difficulty with that process is that it will not make 

 an uniform article, and it is supposed by manufacturers that it 

 will amount to nothing. 



Prof. Seely — I will answer Mr. Fisher's question. Mr. Sel- 

 loch calls it the residuum steel, Mr, Fisher calls it cast-iron. I 

 think it is neither, but an alloy purely. Franklinite ore is 

 ninety-five per cent, of iron, and the remainder zinc and manga- 

 nese. Steel is ninety-five per cent, of iron, and the remainder 

 carbon and nitrogen. It happens that the zinc and manganese 

 give to the iron some of the properties of steel. Now if we 

 attempt to apply the Bessemer process and introduce air, it will 

 form an oxide of manganese and oxide of zinc, which would ruin 

 the iron. 



Mr. Selleck. — A little Franklinite sprinkled over iron and 

 heated, will melt and run like quicksilver all over the surface, 

 making the iron as hard as steel. If Franklinite iron is put upon 

 the point of the caulks of horse-shoes, it will make them so 

 much harder than the iron that the wear of the shoe will leave 

 a cutting edge always sharp at the point of the caulk, and pre- 

 vent slipping upon the Russ pavement. 



Mr. Tillman. — The effect of the admixture of manganese seems 

 to add greatly to the strength of iron. The atomic weight of 

 iron is 28, and that of manganese is 26.50; and manganese is 

 magnetic, like iron at very low temperatures. 



Mr. Selleck. — Why does not sulphuric acid act upon Frank- 

 linite ? 



Mr. Tillman. — I have only seen it tried with nitric acid, which 



