64 ANNUAL OF SCIENTIFIC DISCOVERT. 



undor the pressure of their own atmospheres, or by means of 

 mechanical appliances. The gases and vapors which are em- 

 ployed for the purposes of this invention may be previously mixed 

 with the air lurnislied by the blast, or may be caused to meet the 

 air in the furnace or at the tuyeres. The proportions of the mix- 

 ture, when a combination of gas or vapor and air is employed, are 

 subject to constant regulation by valves. One very convenient 

 mode of obtaining combustil)le gases for the purposes of this in- 

 vention is to irenerate coal "fas in the usual wav, and then carbonic 

 oxide, and to blow air or carbonic oxide gas under pressure 

 through the retort containing the residual coke. For the purpose 

 of carburizing the iron, whether in or out of the furnace, as may 

 be desirable, coal gas or other carbides, or other materials con- 

 taining carbon, are blown through the furnace, or brought into 

 contact with the molten metal by blowing them throu":h it. Car- 

 bon in any suitable form or combination may also be directly in- 

 troduced into the furnace for the purpose of carburization, and 

 although generalh'for smelting purposes it is desirable to exclude 

 all solid mineral fuel from the furnace as part of the charge, yet 

 where a suspension of operations is necessary, such a charge of 

 coal, coke, or otlujr fiud may be introduced into the furnace as 

 will prevent the materials, on renewal of work, from falling through 

 the cruciljle or anv iron remaining: therein or below it from beino' 

 permanently solidified. When purification is required, hydroflu- 

 oric acid is blown through the molten metal in its way from the 

 furnaces, the gases being mixed with common air, or with some 

 gaseous diluent. — Mechanics' Magazine, Sept., 18G9. 



BESSEMER ON THE HEATON STEEL PROCESS. 



Mr. Henr}' Bessemer, the inventor of the Pneumatic process, 

 addresses a letter to the '* London Times," under date of Dec. 1, 

 in reply to an article in that paper, to the effect that by the Bes- 

 semer process no good malleal)le iron or steel can be produced 

 from inferior pig, while, b}' tiie Ileaton process, steel is produced 

 from very inferior pig iron, and steel of the first class. The ex- 

 ception taken b}' Mr. Bessemer in his letter is, that the steel pro- 

 duced by Mr. Ileaton is not iiomogeneous or cast steel, but has 

 the general nature of puddled steel; that is, is laminated and 

 lilnous in form, besides appearing in the shape of ])orous steel 

 sponge, similar to the iron sponge produced from a Swedish fur- 

 nace, lleaton's result, Mr. 13essemer says, can only be converted 

 into cast steel by the old Sheffield crucil)le process, at a cost of 

 from o to 6 pounds sterling per ton. The nitrnte of soda (270 

 pounds) necessary to reduce a t©n of pig by tiie Ileaton process, 

 costs 6 pounds sterling on the average ; so that while the inferior 

 pig used l)y the Ileaton costs 5 pounds less per ton than that used 

 by the Bessemer process, the cost of tlie nitrate overbalances this 

 gain on the ton by one pound sterling. The result is, that 

 laminated steel, which must be remelted at a cost of 5 or 6 pounds 

 to the ton to produce cast steel, costs a pound more to the ton by 



