ON THE NATIVE SULPHURETS OF IRON. 2?1 



With the muriatic acid I fucceeded in forming a fmall por- Th« aggregation 

 tion of gas ; but its action foon ceafed, and it was equally im- J" *ome me&fat 

 poffible for me to faturate the acid. It was of twelve degrees defends it. 

 of the areometer, and the powder preferved its colour, The 

 natural pyrites treated in the fame manner does not afford the 

 flighted fufpicion of gas ; but we muft not overlook that art 

 cannot give to its compounds that aggregate condenfation 

 whicli is one of the greateft obftacles to folution. Morveau 

 and Fourcroy have given us very ftriking proofs in the refin- 

 ance they found in diffolving the native oxides of iron and 

 tin. 



The pyrites not being, as I have obferved, an homogeneous Thefe experi- 

 combination, it is evident that we could not expe6t to difco- ments couW not 

 ver the true proportions of fulphur wherein iron ctould attract p 0rt i ons Jfful- 

 by thefe previous experiments ; for which reafon I made the phur. 

 following. 



In order to depend in the flrh 1 place upon pure filings, we Other experi- 

 muft begin by heating them gently, and for a considerable i»« nts - 

 time in a glafs retort. Under thefe circum fiances, it is not a 

 little remarkable to obferve, that filings cleaned with the mag- Iron filings af- 

 net, and kept in well-clofed bottles, afford neverthelefs a very ^d ammonia, 

 ammoniacai water, and even muriate, if I am not deceived 

 in the tafte of the fluid which efcapes. 



One hundred parts of filings heated to a low red heat in a Direct combiha- 

 retort, and fulphur being let fall upon them, acquire an in- tion of iron and 

 candefcence which was noticed even by the ancient chemifls ; 

 but they do not become faturated. The increafe is found to pirft degree of 

 be only twenty or thirty parts. After pounding the produd, Mphurization; 



ill •• •/ -a. r i u j / •<. * ju . 6opa.tsofful- 



then mixing it with lulphur, and expoiing it to a red heat, a p^ ur t0 100 - u0 ^ 



refult is obtained, which weighs pretty conftantly 1 59 ; but 

 which, I think, may be fet at 160, on account of the impu- 

 rities of the iron. 



The product is iron fulphurated to the firft degree. It may Its appearance. 

 be fufed, and even melts in the retort, if harpfichord wire be 

 ufed, and maintains itfelf without alteration. Its colour is 

 metallic, but dull and confiderably different from the golden 

 colour of the pyrites. In a word, it is the fulphuret which is 

 proper to afford fulphurated hidrogen gas. 



In order to difcover the excefs which this fulphuret can Second degree* 

 ft ill abtbrb, provided its temperature be lefs elevated, I JJjJJJf t0 

 treated two hundred grains of filings with the before-men- 

 4 tioned 



