ON THE PIUIT2 OF FRANCE. 2|3 



lis fra6lure is unequal, with a fine grain, approaching to a Its frafture is 

 fplintery fraaure. finX']* ""''^ ' 



It admits of being fcraped by a knife, and yields a diift of Yields to the 

 a bright grey colour : ik is tender, and does not adhere to the knife, does not 



. . •. • 1- , o , . , adhere to the 



tongue, (hough it is a little unctuous to the touch. tongue, and is 



Befides the ilze of its crylials, their faces, the fubftances a little unftuous 

 to which they are found attached, added to the charaders de- '°^ ^ *°"*^ * 

 fcribed, eilablifti the identity of this mineral with the pirite 

 of Saxony. 



The cryftals found in Auvergne are more perfc6l than thofe The external 



of Scheenberg; they exhibit no alteration, and the purity of ^Jj"^^^JJ°^ 



their form removes ail doubt of there being any necefliiy to leave no doubt 



clafs this fubflance as a new fpecies. ' °( ^^i' ''^.^n 



^ with the pirite ot 



Saxony. 

 AnaJyfis by M. Drappier. 



The pirite of France, feparated carefully from its bed, and Analyfis of the 

 reduced to a fine powder, is attacked and difcoloured by mu- ^"""^^ ^ '"'■^ 

 riatic acid. This acid diHblves the oxide of Iron, the colour- 

 ing principle, and a portion of the alumine: but as it leaves a 

 confiderable refidue, on whicli it appears to have no a61ion, 

 M. Drappier thought the method of analyfis Qiould be changed : 

 he then took 100 parts of this fubftance, and kept it at a red One hundre<j 

 heat in a crucible of platina for half an hour; after it was P^*^*? '°'^ 7 ''y 

 cooled, there was a lofs of feven parts. The remaining 93 The remainder 

 parts were heated in (he crucible ior three quarters of an hour, fu fed with pot- 

 with three times their weight of cauftic potadi, pi^'''ned by ^^j^^^° ^"J"^ 

 alcohol. The fufed mafs, detached from the crucibje by dif- 

 tiijed water, dilTolved entirely in muriatic acid. The fululion The folution 

 evaporated almoft to drynefs, and then diluted with a frefti ^'^^P""^^.^ and 

 quantity of water, let fall a white precipitate, having all the ^ater depofits 

 charaflers of filex. This precipitate waflied carefully and 46 parts preci- 

 well dried, formed 0,46 of the fubftance fubmitted to expe-^"^^^' 

 riment. 



The remainder of the muriatic folution was dccompofed by The refidue 

 cauftic potatb. It immediately formed a precipitate, which ^''"'^^'^ ""^"l 



r f,T- 1 I • • . ^ r 1. 1- • , I ?auftic potaflx 



loon dillolved agam in the excels ot alkali, with the excep- leaves i-i parts 

 tion of 2|- parts of oxide of iron. '"°^ oxide. 



The alkaline folution fatuiated by an acid, depofited 42 The alkaline fo- 

 parts of an earth, which had all the properties of alumine. All '"^'"'^ ^^^"'■^^^'* 



1 /• • • t f 1 -11 /, 1 "y ^" ^'^'^ ^^■ 



thele precipitates, before they were weighed, were wallied pofits 4s parts 

 parefuHy, and heated to redncls in a crucible of platina. alumine. 



Anali/fis 



