732 THE POPULAR SCIENCE MONTHLY. 



man steel " was made directly from the ore or a suitable 

 quality of " pig iron " was used. The operation, when ore was 

 employed, consisted in removing the oxygen, and then by appro- 

 priate manipulation, together with a regulation of the blast and 

 heat, the iron was combined with carbon derived from the fuel to 

 such a degree as to convert the metal into a mass of crude steel ; 

 this was carefully drawn under a light, quick-working hammer 

 into bars about an inch square ; six or eight pieces of these bars 

 were made into a " pile," welded together, and drawn into smaller 

 bars. This process, called " refining/' was repeated a number of 

 times, and the quality of the resulting steel was designated by 

 the terms " single/' " double," or " triple refined," according to 

 the number of weldings and hammerings. When " pig iron" was 

 used, the operation consisted in so manipulating the metal and 

 regulating blast and heat that a portion of the carbon in the 

 " pig " remained in the resulting " bloom " of crude steel, which 

 was subjected to the same " refining " as has just been described. 



All the early attempts to make steel in America were in the 

 " German manner " ; but it was soon discovered that the ores and 

 pig irons available were not of a proper quality, and attention was 

 early directed toward the " cementation process," the details of 

 which were fully described by Reaumur in 1722.* 



The operation of making " cemented " or " blister " steel con- 

 sisted essentially in packing bars of wrought iron in charcoal- 

 dust in long boxes or "pots" made of sandstone or fire-brick. 

 These " pots " were covered as nearly air-tight as possible and 

 subjected to a high degree of heat (not, however, sufficient to melt 

 the bars of iron), which was regulated as to temperature and 

 duration according to the contemplated use to be made of the 

 steel. As a rule, the higher the temperature and the longer time 

 it was kept up, the greater the degree of carburization of the bars 

 in the " pots " and the harder the resulting steel. When the iron 

 is packed in the charcoal, one or more bars are allowed to project 

 through openings in one end of the " pots " ; these bars are re- 

 moved at proper intervals of time, and from their appearance 

 when cold the progress of the operation was judged. When the 

 process of " cementation " was finished, the furnace was allowed 

 to cool, and, as soon as men could work therein, the metal was 

 removed from the " pots," and it was found that it had undergone 

 a great change : instead of having a smooth surface, it was cov- 

 ered with a large number of " blisters " of varying size and thick- 

 ness (hence the name " blister steel "), and, although when put into 

 the "pot" the metal was very fibrous and tough, it was found 



* L'art de convertir le fer forg6en Acier, et l'art d'adoueir le fer fondu, ou de faire dea 

 Ouvragcs de fer fondu aussi finir que de fer forge. Par Monsieur dc Reaumur, de P Aca- 

 demic Royale des Sciences. A Paris, 1722. 



