20S On ike Fujion of Malleable Iron, Mc, 



with cold-fhort iron, the extent of the change is by far the 

 nioft conliderable. Its lofs by weight is aho much beyond 

 ihat fuftaiiied bySwedifh iron. 



I meant to have inferted a few experiments with iron un- 

 commonly red-(hort; but the number already adduced will, 

 I am afraid, have the appearance of prolixity. Suffice it to 

 fay, that I have obtained data i'ufficicnt to be able to profe- 

 Gute, with fome hope of fuccefs, an inveftigation of the caufcs 

 of red- and cold-(hort properties in malleable iron. I (hall 

 conclude this fubject with the following remarks : — Iron^fed 

 with window glafs ahvays has its upper furface impreflfed with 

 u beautiful cryliallizalion, often coloured. This circumftance 

 never takes place when flint glafs is ufed. When bottle 

 glafs is ufed, the crylta^lizaiiou is not fo frequent, and fel- 

 dom fo perfect, as with window glafs. Crvltallization is rtill 

 Ir^fs frequent, and lefs perfect, when a mixture of cUy and 

 lime is employed. When carbonate alone is fufed with iron, 

 the fame want of cryftallization takes place as when flint 

 glafs is ufed. 



The fufion of malltable iron is produAive of the difen- 

 gagement of an elaliic fluid, the efcape of which, I am in- 

 clined to think, is one of the chief caufes of the alteration of 

 its quality. In moft cafes, when the cover was ftruck oflT 

 while the matter was ftill rtd-hot, a burft of whitifli blue 

 flame iflued from the mouth of the crucible. In others, 

 where the fufion had been of fliort duration, or lefs perfecSt, 

 the upper furfliceof the glafs became covered with thin tranf- 

 parent bul)bles, each of which appeared filled with a dull 

 lambent blue vapour. Thefe were eafily perforated with a 

 pin point, and a flight explofion was heard from each, ac- 

 companied by a momentary combuftion. In burning, this 

 fubftance refembled hydrocarbonate *. 



Experiment, which was omitted in the former commur 

 nication, to prove that the carbonic acid was neutral in the 

 fufion of iron, or at leafi: was not productive of fteel. 



Grains. 



Italian raw marble - - 6og 



Steel oxide, from the tilt anvil block t 50 



This mixture was reduced to a fine powder, and completely 



triturated. It was then introduced into a Stourbridge clay 



pot, and expofcd to a heat fuflacient to fufe it. When cold, 



'• This faft may lead to a more (Imple explanation cf the formation of 

 infl.iinmrtble air than that adopted by Dr. Priertlcy or Mr. Cruiklhank. Bar 

 iron with a mixture of ^la(s, wichout the addition of carbon or its acid in 

 Jimc, are here proi!ii(ftivc of an elaftic fubftance poffefTed of finiilar pro- 

 jtrfics as thdt obtained ia their experiments. 



the 



