jjj Btrgmjii's Prscefi for iUfciVtrlng Pho/phoriu in IrM. 



obtain the grcateft poITible quantity of c;irburct of iron from any kind of (Icel, the acid muft 

 be neither too much nor too little concentrated. I have obfervcd that the befl. proportion 

 between the acid and the water was one of the former to five of the latter, and that coarfe 

 filings or turnings of fteel were preferable to fine filings or pieces of confidcrablc fize. 



Mod of the inconveniences here mentioned do not cxill wiih regard to the muriatic acid, 

 at lead in fo evident a manner; bccaufe it is never fo concentrated as the fulphoric acid, 

 has a (Ironger affinity for the oxide of iron, and forms with this metal a very folublc fait. 

 But it cannot be employed to determine, in one and the fame operation, the proportions of 

 tavburet of iron and of phofphorus ; becaufe it decompofes the phofphate of iron, and renders 

 •it neceflary to ufe a c.iuftic alkali to precipitate it by double affinity, which may be attended 

 with fomc inconvenience. 



The method xve have propofed to determine the quantity of carbone contained in ftccl, is 

 therefore preferable to this in every refpetl. 



SECTION viir. 



RtfleSions on the Means pnfcfrd by Btrgmati to difcovcr the Prefciicc of Phofphortu in IioK 



and Steel, 



BERGMAN, in his DifTertation on the Analyfw of Iron and Steel, docs not fpeak of 

 the prefence of phofphorus or fiderite, which he found only in cold (hort iron. 



It is neverthelefs very unlikely, that, among the very numerous famples of iron and fteel 

 which he examined, there (liould have been none which contained phofphorus, Gnce the 

 four fteels which conllitute the fubjeft of this memoir all prefented quantities very con- 

 fiderable, though they appeared of fufficiently good quality for the ufes in the arts. I fuf- 

 pe£\, therefore, that this chemid's not having found it was owing to a want of attention to 

 the probability of its exiftence, or elfe, that the means he made ufe of were not adapted to 

 dcted its prefence. 



The following is the method he propofes for this purpofe, in his DiiTertation on the caufe 

 of the brittlenefs of cold diort iron : 



He takes a bottle A, of the capacity of about I7 cubic inches, into which he puts 16 

 loths of crude iron, which affords the cold fliort iron. Upon the iron he pours fix cubic 

 inches of didilled water, and half an inch of concentrated fulphuric acid. As foon as the 

 effcrvefcence is ended, he filters the liquor, and receives it in another bottle B, of the fame 

 contents as the firft. He wadies the rcfidue in the bottle A, until the filtration fills the 

 bottle B. This being done, it is obfcrved that the fluid in B, which at firft was clear, 

 becomes turbid and white. The powder does not fettle until after feveral hours. He 

 pours on the iron which remained in the bottle A a fecond quantity of water and acid 

 equal to the fird ; when the effcrvefcence is over, he pours the liquid into a third bottle C. 

 He repeats this manoeuvre a third and fourth time, &c. and colled^s the liquors in the 

 yeflels marked D, E, See. The phenomena were the fame in each of thefe operations ; but 

 the fifth folution in F remained clear for feveral weeks, at the end of which it formed a 

 ■ flight cloud. The fixth folution depofited nothing in the fame fpace of time, tliough 

 much iron remained undiflblved. 



9 I repeated 



