en tbe %TanuJq&iire of Malleable Iron. *$$ 



Conferences. An acurate chemical analyfis of the various 

 ftates and qualities or Britifh manufactured iron, aecom~ 

 panied by a flmilar development of the component parts of 

 the foreign fabrics, would prove an intercfting contrail, and 

 could not fail ultimately of producing infinite advantage to 

 that department of labour. 



I {hall not, at prefent, enter into an inveftigation of the 

 probable reafons which conftitute this difference, but con- 

 fine ■ myfelf to a fuccinct account of feveral procetTcs in which. 

 I have'obtained malleable iron, often fuperior to the common 

 run of Britifh manufacture. In contemplating thefe mani- 

 pulations followed out in the large way, I uniformly found 

 that, although feme fabrics pofleiied comparative excellence, 

 yet that all were deficient in obtaining a quality of iron equal 

 in appearance and fracture to the foreign. 



In all thefe proceiTes it was evident that if the contact of 

 pit- coal, confidered as a more impure fuel than wood, was 

 hurtful to the quality of the iron, then all our bar-iron 

 would be fo injured, as all of it is manufactured either in 

 contact with lueh fuel, or the flame of it, or both. The 

 point therefore wifhed to be gained was the making of bar- 

 iron without bringing the metal, while in fufion, in contact 

 either with the flame of pit-coal, or with the ignited coaks. 

 My ftfft crude attempt was in 1794 with crucibles and roafted 

 ironftone. I conceived that by introducing jult as much 

 charcoal of wood as would remove the oxygen of the ore, 

 that malleable iron would be the refult. Experiment, in 

 fome nieafure, jufiified this conjecture: but a want of uni- 

 formity in the refult proved the fallacy of this mode of ope- 

 rating. When the temperature was moderately raifed, I 

 found the iron partially feparated, and, in a malleable ftate, 

 entangled amongft the earths of the ore : but, when a higher 

 'degree of heat was brought on, the greateft part of the iron 

 was found precipitated in the form of a button. The iron m 

 this ftate was malleable: but fo exceffively red-fhort as to be 

 incapable of drawing at any (hade of heat beyond faint red. 

 1 In varying thefe experiments, and uiing a greater propor- 

 tion' of charcoal than ufual, I was furprifed to find, that after 

 a long and violent heat no part of the iron had entered into 

 fufion. The pieces of iron-ftone were firmly connected to- 

 gether, pofiefied of the original acutenefs of angle and frac- 

 ture. Their appearance and,furface was dark and metallic, 

 and, upon attempting to part them, I found them attached 

 to each other bv a fpecies of metallic fibre, which twifted 

 repeatedly before breaking. This was a fpecies of welding I 

 had never before witneffed. I found the whole mafs fuffi- 



ciently 



