Convirjon of Iron into Steel by the Diamond. 105 



Into a fmall hollow cylinder of foft iron, clofed at one end, I put fome diamonds, and 

 having introduced into the cavity above them a ftopper of the fame foft iron, which fitted 

 exa£Hy, the two pieces were rivetted together at the top. The ftopper was nearly in con- 

 ta£t with the diamonds, but I did not fill up the intermediate fpace with iron filings, as 

 the French chemifts did, for fear of introducing fome fragments of fteel from the file. 

 Having placed the cylinder in a Heflian crucible, I furrounded it with a mixture of dry 

 fand and clay*. I luted a lid on this crucible, and placed it in another, on which a lid 

 was alfo luted, and a fmall clay cafe containing a pyrometer piece, was attached to its out- 

 fide, I wifiied to fubje£l: the iron to a heat not exceeding 150°; for which purpofe I 

 'placed the crucibles in a forge. After they were red hot, the fire was raifed, till I thought 

 it had attained the pitch defired, and was then continued as equal as poflible for an hour. 

 The pyrometer indicated 151°. 



On opening the crucibles, I found that the upper part of the iron had been melted, and 

 I obferved feveral bright metallic globules adhering to the compared mafs of fand and clay 

 next the iron. "J^hc lower part of the cylinder retained its fiiape, but except a portion of 

 the bottom wTiich remained fmooth, was bliftered on the furface. Having pollflied both 

 ends of it, I found that on touching them with diluted nitric acid, they exhibited the fpot 

 which that acid ufually produces on fteel. The fpot on the end which had been fufed, 

 was confiderably darker than that on the other. I cut off the portion which had remained 

 fmooth, and having heated It red hot, and plunged it into cold water, it became fo hard, 

 that no impreffion could be made on it with a file. Several cavities were found within the 

 cylinder, but the diamonds had totally difappeared. 



The whole cylinder was thus converted into fteel ; one end being reduced to the ftate of 

 caft fteel, and the other remaining in that of cemented fteel ; from which It feems proba- 

 ble, that the upper part alfo had pafled into the ftate of cemented fteel before It began to 

 melt. It may therefore be inferred, that diamond may be combined with iron foas to form 

 fteel by the fimple procefs of cementation. 



Mr. Muftiet, of the Clyde Iron Works, has lately publlflied In the Philofophical Maga- 

 zine, an account of certain procefles, with a view to prove " That the experiment per- 

 formed at the Polytechnic School refpe£ling the converfion of iron into fteel, by means of 

 the diamond, was not conclufive." The manner in which Mr. Muftiet's experiments were 

 conduced, appeared to me to be liable to fome objeftions ; and it was therefore neceflary 

 to afcertain, how far the diamond had contributed to the formation of the fteel in the laft 

 experiment, by expofing part of the iron of which the cylinder was made to the fame de- 

 gree of heat in fimilar circumftances. Accordingly, a portion of the fame iron was im- 

 bedded in fand and clay, and the apparatus was arranged, and the forge managed preclfely 

 as In the laft experiment. At the end of an hour, the crucibles being withdrawn from the 



* The quartzy fand, called Lynn fand, waflieij and heated red hot— Stoui bridge clay. 



VoL.IV.— June 1800. P fire, 



