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Indiana University Studies 



be made. As soon as the railroad officials realize the amount 

 of this material that could be carried if more favorable rates were 

 made there will be a tendency to make better rates and condi- 

 tions. 



One thing that has held back the development of this outlet 

 for the waste stone of the district is the fact that in the past many 

 quarr}^ operators have adopted the practice of giving the waste 

 stone to the railroads if the latter would remove it, even going 

 so far as to load the material free of charge. Thus it will be seen 

 that the entire profit of the transaction has gone to the railroad 

 and it would therefore be to their interest to maintain high rates 

 on shipments of this material by individuals to the blast furnaces. 



The total amount of limestone used for flux in this country in 

 1913 represented a value of $11,103,989 of which Indiana pro- 

 duced $199,995 worth, ranking ninth in this industry. The 

 above total represented a production of 22,620,961 long tons, 

 at an average price of 49 cents per ton. 



The production in 1912 was 20.190,554 long tons with a value 

 of $9,937,772, an average price of nearly 50 cents per ton. 



Limestone and Lime in the Manufacture of Glass. 



'^Glass is an amorphous, transparent, or translucent mixture 

 of silicates, one of which is alwaj^s that of an alkali." The above 

 definition of glass is taken from a standard work on industrial 

 chemistrj^ This study is concerned only with the glass which 

 contains calcium as the alkali metal. In technical discussions 

 of glass two general classes are recognized: lead glass and lime 

 glass. The lime glass is more widely used, harder, cheaper, 

 less fusible, and has greater brilhancy than the lead glass. The 

 essential materials for the manufacture of lime glass are silica, 

 an alkah (soda or potash), and lime or limestone. In the manu- 

 facture of glass, materials free from iron or iron compounds must 

 be used. The alkalis most commonly used are the carbonate 

 or sulphate of sodium or potassium. The carbonates fuse more 

 easil}^, but the sulphates are more commonly used because they 

 are cheaper. With the sulphate, powdered carbon must be used 

 as a reducing agent, the reaction being as follows: 



2Xa2 SO4 + 6Si02 + C = 2(NaoO, BSiOo) + 2SO2 + CO, 

 Or, 2Na2S04 + 2SiOo + C = 2XaoSiO,3 + 2SOo + CO2 



Common salt as a source of sodium in the manufacture of 

 glass has not yet reached any extended use, but some method 

 whereby it can be used economicalh^ is sure to be perfected. 



