METALLIC 3ULPHURETS. 20$ 



employed by Mr. Humboldt for the purpofe of afcertaining water, and am- 

 the quantity of nitrogen mingled with nitrous gas ; and that J 110 '"* ^L^I) 1 " 

 experiraentalift, in conjunction with Mr. Vauquelin, has at- hidrogen. 

 tempted to prove that the procefs of abforption is owing to an Hiftory. Hum- 

 immediate decompolition of the nitrous gas by the water of. bolc L anc * Xf u " 

 , ri • • r I v . t • r •• quelin think the 



the iolution j m conlequence ot which nitrate ot ammonia is gas \ s completely 



formed. decompofed at it* 



This conclufion is publifhed in the 28th volume of the An- ai [ d a a mm r P n ia"* 

 nales de Chimie. In the 39th volume of the fame work, 30 formed. 

 Meflidor, An 9. p. 1. Mr. Berthollet Hates, that nitrous acid Berthollet ap- 

 is probably formed during the abforption of nitrous gas by fo- tia j decompofi-" 

 lution of fulphate of iron ; in confequence of the evolution of tion j 

 a portion of its nitrogen, and in confequence of the more in- 

 timate union of its remaining constituent principles. Yet, in but neverthe- 

 the fame paper, he details an experiment on the application lef s is ' ed *° fu *~ 

 of heat to an impregnated Solution, which was attended with ren ces of a&ion 

 remits fimilar to thofe defcribed above ; and in confequence of f rom tempera- 

 which he is induced to enquire, " If the fulphate of iron is 

 capable of exerting two different actions in nitrous gas ; one 

 tending fimply to abforb it, and the other to decompofe it ?" 

 p. II. 



The general account that has been given in this Note of The author's 

 the true nature of the procefs, is extracted from " Refearches, ex P enmen,s 



r . . . were made over 



Chemical and Philofophical, concerning Nitrous Oxide, pub- mercury ; and 



limed in June, 1800." The experiments upon the abforption eonfe( l uen I ^ he 



j j ** i • r r was not, like 



were made under Mercury ; and, in conlequence, the agency thofe chemifts, 



of the atmofphere, which appears to have milled the cele- m ^ ed b y the 



brated foreign chemifts juft quoted in their conclusions, was mo fphere. 



avoided. 



».,■■■■ i ' ■ - 



VII. 



On certain Metallic Sulphurets. % Proust, Profejfor of Che- 

 mijtry at Madrid *. 



1 LONG fuppofed, that the iron in pyrites was oxided at 111 founded opl- 

 the minimum, and, fupporting my opinion by fome analogies, "J^ j n ^ yx \^ % 

 I publiihed it in the year 1795 ; but when my attention was is oxided. 

 recalled to the Subject, by reading the Memoir which Vau- 



* Journal de jPhjfique. Thermidor. 9. 



quelin 



