Dl'fcVvat'iotis on the Aitalyfis of Sleek att 



Me innccurate, as we Hiall fljew in ilis courfc of the prefe.it memoir, and as it alfo appears 

 from the difTercnt refults he obtained from the analyfis of various kinds of ileel, the ufual 

 properties of which did not indicate fo great a difference. 



It is admitted, fince the valuable experiments of Bergman, and particularly thofe cf 

 LerthoUet and Monge, that fteel differs from pure iron only from the prefence of a ccr- 

 tam quantity of cavbone, which is intimately con-.bincd ; a proportion which perhaps may 

 admit of lome degree of latitude; but which, neverthelefs, if above or below a certain 

 quantity, affords either an over-cemented, brittle, and too fufible kind of flee!, or elfe ftce! 

 which too nearly approaches to iron in its qunlities. 



If flee! were merely an.l conftantly a combination of carbone and iron, in determined 

 quantities, it would be ea(\- to afcertain tliis point once for all; but it almolt always happens, 

 that aeel contains f.lex, phofphorus, and fometimes manganefe, of which the influence' 

 upon the qualities of the fteel is not known, even on the fuppofition that fteel is necef- 

 farily no more than a combination of iron and carbone. 



If we admit that thefe different fubftances are not indifpenfable to the conftitution of 

 fteel, It muft neverthelefs be allowed that they will affecT: its properties by greater or lefs 

 modifications, dependent on tlieir own quantities refpeftively. 



If, therefore, as it feems out of doubt, the various qualities of iron and fteel arifc from 

 the feveral principles of which they are compofed, and their refpedive proportions, it is 

 equally interefting to philofophy and the arts to determine, by chemical experiments, what 

 influence each of thefe principles may exert in the combination, and to find by fimp'le, ready 

 and cheap experiments, in what ufes thefe metallic fubftances maybe moft advantageoufly 

 employed. But in order to arrive at this defirable termination, a more precife knowledge is 

 required of the ufual properties of the known kinds of iron and fteel, compared with the 

 chemical nature of thofe matters. There is not, however, any other method than that of 

 examining the two means at the fame time, by which we may fucceed hereafter in eftablifliing 

 and fixing by chemical eflays the qualities of the kinds of iron and fteel already ufed, and 

 even thofe which may hereafter be fabricated. 



It may be eafily conceived that this undertaking would demand a great number of ex- 

 periments. For it not only requires a knowledge of the number and nature of the elements 

 neceffary for the formation of fteel of the beft quality, but likewife the proportions of thefl 

 elements, which may be infinitely varied, and to determine befidesthe modifications which 

 may be produced by various quantities of fubftances not eiTential to the conftitution of tliis 

 metal. 



In the mean time, till circumftances ftiull permit the execution of this ufefui plan 

 I proceed to offer the refults of the analyfis of four kinds of fteel, the difficulties I have 

 found in the progrefs of this work, the means I have ufed to overcome them, and the me- 

 thods I have fubftituted, inftead of ancient proceffes, to afcertain and meafure the effential 

 and accidental principles of the fteel. 



SECTION II. 



8TEEL, KO. 864 — SMALL PIECE. 



Exptrlment I. 576 grains, or 30,57 grammes, of this fteel, reduced into filings, and dif. 

 folved in fulphuric acid, diluted with five parts of w.uer, afforded 1,98 grains of black refidue. 



Expetlmtnt 



