INDUSTRIAL PROGRESS DURING THE YEAR 1875. cclxv 



worked over, and the cost of steel equal in grade to Bessemer 

 would not exceed the latter. 



In Bessemer practice the experimental trial of the hot blast 

 is worthy of notice. The Berg- unci Hiittenmcinnisches Jahr- 

 buch, in which the record of the trial is made, states that at 

 the Bessemer Works at Zeltweg, Germany, some fifty or more 

 charges rim with a blast heated to nearly 1300 Fahr. The 

 result of these trials demonstrated, what had before been sur- 

 mised, that a slightly carbonaceous iron could be used in the 

 Bessemer process with hot blast. It was likewise found that 

 more rail -ends could be thrown in than ordinarily. Iron 

 that with cold blast could stand only twelve per cent, of rail- 

 ends took up with hot blast eighteen per cent. It w r as, how- 

 ever, found to be impossible to conduct the operation con- 

 tinuously, because of certain practical difficulties that were 

 met with. The chief of these was the rapid wearing of the 

 bottoms of the converters while one would ordinarily stand 

 about fifteen charges, it was found in these trials to be use- 

 less often after only two charges. Another difficulty was 

 found to be the excessive heating of the parts of the appara- 

 tus in contact with the hot air. These practical troubles, it 

 is said, caused the abandonment of the experiment, though 

 the results obtained were sufficiently favorable to warrant 

 the statement that the employment of the hot blast in Bes- 

 semer practice is attended with advantage, though the ma- 

 nipulations demand experience and practice. 



During the past year the results obtained by Sir Joseph 

 Whitworth and others in compressing steel in the liquid 

 state by hydraulic pressure, in order to secure more perfect 

 homogeneity of structure and increase in strength, have at- 

 tracted considerable attention. In common practice, steel 

 which is cast into ingots is more or less honey-combed by 

 bubbles of gas distributed through the structure, which hon- 

 ey-combing it is endeavored to remove after solidification by 

 the processes of cogging, hammering, and rolling the mate- 

 rial while in a heated state. To avoid this honey-combing, 

 some manufacturers have succeeded in producing thorough- 

 ly sound steel castings by " dead melting" the steel, employ- 

 ing moulds with a non-conducting lining and running the in- 

 gots with a sufficient head. We are not aware that any com- 

 parative tests have been instituted with steel so cast and 



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