C 466 ] 



Xt. Report made to the French National }n/litute } hy C. 

 GUYTON and DARCET, in regard to the Refults of the 

 Experiments of C. Clouet, on the different States of 

 Iron, and the Converfion of it into Cajl Steel. From the 

 Journal des Mines, No, XLVt 



X HE memoir of C. Clouet is entitled Refults of Ex- 

 periments on the different States of Iron. He firft treats of 

 Ihe combinations of iron and carbon. A thirty-fecond part 

 of carbon, fays he, is fufficiertt to convert iron into fteel : a 

 quantity of it equal to a fixth part of the weight of the iron^ 

 gives a fteel more fufible artd ftill malleable; but beyond 

 that term it approaches to caft-iron, and has no longer fuf-^ 

 ficient tenacity. By increafing the dofe of carbon you in- 

 creafe the fufibility, and it panes at length to the ftate of 

 grey caft iron. 



The particular kind of caft iron refulting from a combi- 

 nation of iron and glafs, is the fecond obje& which engages 

 the attention of C. Clouet. Glafs never enters into it but 

 in a very fmall quantity, yet its properties are changed t 

 This iron, though exceedingly foft under the file, when 

 brought only to a cherry-red heat, divides itfelf under the 

 hammer ; when poured into the ingot-mould, mrinks con- 

 fiderabVy; and when formed into plates, tempering gives 

 them the grain of fteel, and renders them more brittle, with- 

 out giving them more hardnefs. Charcoal duft added to 

 glafs changes the refult, and increafes the fufibility; but the 

 dofe has a fenfible influence on the produces. From a thir- 

 tieth to a twentieth in one part of iron gives a very hard 

 tempered fteel, which fuffers itfelf to be forged at a cherry-* 

 red heat, and whieh has all the properties of caft fteel. By 

 employing more carbon, you get only caft iron. 



The affinity of iron for carbon is fo great, that at a high 

 degree of temperature it even takes it from carbonic acid. 

 This he proves by the following experiment : — If you put into 



a crucible 



