Experiments en Iron at elevated Temperatures^ bfc, 109 



not found that foft iron, in one folid piece, in fragments, or in filings, may be perfeQly 

 fufed without undergoing any change in its properties. 



A cylindrical piece of foft iron, about an inch in length, and half an inch in diameter, 

 after being placed on its end in a Heffian crucible, and furrounded with quartzy fand, was 

 cxpofed to a ftrong heat in a. furnace. The upper half of the cylinder loft its ftiape and 

 funk down : but the iron retained its original properties. 



The fufibility of foft iron is proved in a more fatisfaftory manner by the following ex- 

 periments : five thin flat pieces of foft iron, making when laid together half a cubic inch, 

 foftened into one folid mafs, which ftill poflefTed all the properties of malleable iron. 



I took two Cornifli clay crucibles, and in one placed a fmall cylindrical piece of foft 

 iron, which weighed only twenty-five grains, and in the other the fame weight of filings 

 of foft iron. Both were placed, together with a pyrometer, in a Heffian crucible, on 

 which a lid was luted, and the apparatus was expofed to the heat of the forge for three 

 quarters of an hour. Both the cylinder and the filings were melted into buttons. The 

 heat was 158°. 



vVilhing to afcertain whether oxide of iron would unite with foft metallic iron when in 

 fufion, and render it brittle, I mixed fome iron filings with a tenth part, by weight, of 

 fcales of iron from a blackfmith's anvil, in the ftate of fine powder, and put the mixture 

 into a Heffian crucible, included within a'larger, which I placed in the forge, together 

 with another containing fome of the fame filings without oxide, and a pyrometer. The 

 heat was applied for three quarters of an hour, after which I found a folid button in each 

 of the crucibles. The fufion was fo complete, that in the crucible containing the mixture 

 of filings and oxide, fome of the melted iron had penetrated through a very fmall hok, 

 and remained between the interior crucible and the exterior. The heat indicated by the 

 pyrometer was the fame as in the laft experiment, 158°. The workman with whom I 

 tried the malleability of thefe two buttons, faid, he could difcover no difference between 

 them, and that he thought they confifted of the fofteft and moft dudile iron he had ever 

 examined. 



As the iron was here found to be melted at 158°, and as in preceding experiments in 

 the furnace, and alfo in Mr. Barker's reverberatory, pieces of iron did not melt at 153°, 

 it appears that the heat requifite for reducing foft duftile iron to fufion, exceeds 153°, 

 but is not higher than 158°. 



From the refult of the foregoing experiments, I hope it is evident, that foft iron cannot 

 be converted into fteel, by carbon penetrating from the fuel through the crucibles. As 

 Mr. Mulhet has not proved by humid analyfis, that his refults contained carbon, lam in- 

 clined to think, that in certain circumftances, iron may perhaps be combined with earths, 

 fo as to form a compound in fome degree refembling fteel. The experiments publifticd 

 by Clouet feem to afford grounds for this fuppofition. One of thefe I have repeated, 

 namely, the fufion of iron filings with a mixture of carbonate of lime, and powdered 

 crucibles, and obtained a button which became very hard, when heated red hot and 



plunged 



