3 48 Memnir on the Stoves /aid to 



I w3? able to obtain* a fufficient quantity of the globules of 

 iron and of pyrites to afcertainthc nature of them. 

 . A. A hundred pans of the flones of Benares, pulverized 

 in a mortar of hard flone, and fifted through a fine filk fieve 

 tt) feparate the coarleff particles of the iron which cannot be 

 pulverized, were treated v.'ith dihite nitric acid. During 

 this operation there w as difengaged a large quantity of nitrous 

 gas; the acid aiiumed. a yellowidi green colour; the ftony 

 powder became whiliT!!, and, dividing itlelf, increafed con- 

 fiderablv in volume, fo that it refembled gelatinous filex. 

 Sulphureous particles were, obferved floating at the furface of 

 the liquor. 



B. When- the aftion'ofithe nitric acid ceafcd, v\aler was 

 added to the mixture; ithe liquor being filtered, the undif-' 

 folved matter was wafhed, and after dcficcation in the open 

 air it weighed no more than 64 parts. 



C. As the matter treated in this manner was ftiil (lightly 

 coloured, it was boiled with muriatic acid, which, as is well 

 known, unites more C'afily with oxidated iron : it afll'umed 

 alfo a greenifh yellow colour, and the powder became much 

 whiter. After this fecond operation the flone, when wafhed 

 and calcined in a platina crucible, weighed only 47 parts. 



D. The nitric and muriatic acids which had been fuccef- 

 fively poured over the ftone as above mentioned were mixed 

 together and then precipitated by ammonia, of which an ex- 

 cefs was added. Being heated for fome time, the liquor was 

 filtered, and the precipitate was waflied and calcined: it had 

 a brown colour, and weighed 38 parts. 



E. The ammoniacal liquor had a flight blue colour in- 

 clining to violet. Alkaline carbonates produced in it no pre- 

 cipitate; on the other hand, cauftic alkalies formed a white 

 precipitate very abundant, but the liquor loft none of its vio- 

 let colour. This precipitate, when wafhed and dried in the 

 air, had a greenifli fliade, and weighed 18 parts ; calcination 

 reduced it to J3. This matter readily combined with ful- 

 phuric acid, and the rcfult was a folution, which by fponta- 

 neous evaporation produced prifraatic cryftals refembling in 

 tafle and favour thofe of the fulphate of magnefia. It how- 

 ever had a flight grtenifli colour, and at the end of fome mi- 

 nutes produced in the mouth a metallic favour. To know 

 whether the colour and favour of the fulphate of magnefia 

 arofe from fome metallic fubftances it was dillijlved ii\ water, 

 and bydrofulphuretof ammonia being poured over it, a pretty 

 voluminous black precipitate was produced. After walhing 

 and deficcation, however, it weighed only two parts. We 

 friall return hereafter ta this matter. 



. F. The 



