14 ANNUAL OF SCIENTIFIC DISCOVERT. 



steel. By the new system steel is protluced in the Bessemer ves- 

 sel in less than 20 minutes, whereby a great saving of time, 

 fuel, and other expenses is effected. 



The i^rocess may be briefly described as follows : A quantity 

 of pig iron, containing an average quantity of carbon, say 5 

 per cent., is melted in one or more reverberator}' furnaces, accord- 

 ing to the size of the converting vessel to be used, which varies 

 in capacity from 5 to 10 or 12 tons. When the metal becomes 

 fluid, it is run into the converting vessel, to which is applied a 

 stronof blast of air, which combines with the carbon at an intense 

 white heat. This is continued for about 8 or 10 minutes, until 

 the whole of tlie carbon is consumed, when the blast is stopped. 

 In this stage a quantity of metal, containing the requisite per- 

 centage of carbon necessary to form the exact quality of the steel 

 required, is poured into the vessel, and this, combining with the 

 retined iron, gives to the mass all the properties and characteris- 

 tics of steel. The converting vessel may be placed so near to 

 the blast furnace as to allow the iron to flow directly into it ; or 

 the metal, in the shape of pig iron, may be melted in reverber- 

 atory furnaces, as is now generally the case, and thence run 

 directly into the converting vessel. 



From tables showing the comparative values of steel when sub- 

 jected to transverse, compressive, and tensile strains, it appears 

 that the mean of all the specimens experimented on is greatly in 

 excess of iron, which, taken at a breaking strain of 20 tons per 

 square inch of section, gives a ratio of 43.46 : 20, or as 2.17 to 1, 

 being more than double that of iron in its resistance to tension; 

 clearly showing the advantages which steel has over iron in its 

 malleable state, and the important benefits wliich it is likely to 

 confer when rightly applied in constructive art. The experi- 

 ments also indicate the superior resisting powers of steel to a 

 force tending to crush it, and its superiority to iron in all the 

 varied forms of resistances to strain to which it may be subjected. 



That the time is not far distant when steel will supersede iron 

 in almost every case where strength is required, we have every 

 reason to believe, and, assuming that the change will be of great 

 national Toeneiit, we shall hail with the liveliest satisfaction the 

 disappearance of iron and tlie substitution of steel as a superior 

 material for general purposes of construction. — W. FAlRBiUKN, 

 in Quarterly Journal of Science, January, 18G8. 



THE SPECTROSCOPE AND THE BESSEMER PROCESS. 



The application of the spectroscope for conducting the charges 

 in the Bessemer apparatus has become a practical realit}'. By the 

 aid of this instrument the manufacture of Bessemer steel, in the 

 Gratz (Austria) works, has been considerably improved witli 

 regard to that exact uniformity of hardness which formerly was 

 more difficult to insure under all circumstances. The great cer- 

 tainty with which the exact moment of complete decarburization 

 can be fixed by spectral analysis has reacted upon the amount of 



