i^i Experiments on Steet, or tie Cumhlnaitom 



the time when die labours of Reaumur had enlightened the praflice of making natural fteel, 

 and fteel by cementation, the theoryTemamed ftationary, notwith (landing the numerous and 

 valuable experiments of Bergman, Rinmann, Prieftley, &c. until the appearance of the ex- 

 cellent memoir of Vandermonde, Bt:rth6llet, and Monge, in the. Memoirs of the Academy of 

 Sciences for 1786. That the Englifh, who had long fupplied the European market with fteel of 

 Cementation, remained alfo in the exclufive pofleilion of the article known by the name of caft- 

 fteel, which, though confined to certain fine works *, is, neverthelefs, a very valuable branch 

 of national induftry ; that various experiments have been made with fuccefs, on a confined fcale, 

 in France to imitate this product, fince the time when Jars publiflied an account of the me- 

 thod ufed at Sheffield ; but that from a want of precifion in the narrations of thefe procefles, and 

 the difference which is, with juftice, confidered to fublift between the experiments of the la- 

 boratory, and thofe of the manufedturer in his extenfive operations, the art of making caft- 

 Heel was confidered, by the moft eminent French chemifts, asvery far from being publicly known : 

 and Vandermonde, Monge, and BerthoUet, notwithltanding their acquaintance with thefe 

 fads, thought fit to declare, in the public inftrudtions drawn up by order of the committees 

 of fafety, that they could offer nothing but conjeftures on the fubjecl f. In this fituation was 

 the knowledge of the chemifts and roanufa<9:urers of France, when Citizen Clouet refumed 

 his experiments on a largerTcale at thelioufe of the Confervatory of Arts, and the mineralogical 

 fchool at Paris, on the fufion of various kinds of fteel, and the immediate conrerfion of iron 

 into caft-fteel. 



On this fubjeft, the author delivered a memoir to the Inftitute 6f France, which forms 

 the fubjefl: of Guyton's report. 'He firft treats of the combinations of iron and charcoal. 

 One thirty-fecond part of charcoal is fufficient, as he affirms, to convert the iron into ftee! ; 

 one-fixth partofdie weight of the iron affords a fteelwhich is more fufrble, but ftill malleable ; 

 and, aft?r -this term, it becomes nearer to the ftate of caft-iron, and no longer poffeffes enough 

 of tenacity. By augmenting the dofe of charcoal, the fufibility is increafed ; and, at laft, it ac- 

 quires the ftate of grey caft-iron. 



The particular caft-iron, which refults from the combination of iron and glafs, forms the 

 fecond obj eft upon which the attention of Citizen Clouet was fixed. The glafs enters but in 

 a fmall quantity into this compound, notwithftanding which the properties of the inafs arc 

 changed. This iron, though very foft to the file, if heated merely to clierry red, flies in pieces 

 under the hammer : the caft ingot contrafts greatly in cooling ; and when, by careful manage- 

 ment, it has been made into bars, the operation of hardening gives them the grain of fteel, and 

 •renders them brittle, without adding to their hardnefs. 



Charcoal in powder, added .to the glafs, changes the refult, and increafes the fufibility; but the 

 nature of the p.oduft is greatly influenced by the dofe of thefe ingredients. From one-30th to 

 one-20th part of the iron affords fteel capable of a high degree of hardnefs, which may be 

 forged at a low red hear, and has aU the properties of caft-fteel. If more charcoal be 

 employed, theprodudls refemble thofe of the fmelting-furnaee. 



* It is ufed in a great variety of common tools and works in this country.— N. 

 t Phil. Journal II. 102, 



The 



