354 Method tf deleB'mg Sulphur and Arjentt In UrK 

 is the method which mankind have always employed when 

 they did not choofe to fee what was only too evident. It is 

 thus that phlogifton has been made topafs through crucibles, 

 and azot through tubes and retorts. 



I fliall here obferve, that to make ihefe experiments fuc- 

 ceed, it is abfolutely necefTary that the water {liould contain 

 gas in folution, either oxygen gas or carbonic acid gas. The 

 more gas it contains, the iboner organifed azot will be formed 

 in it. 



It is much to be wifhed that chcmifts would examine with 

 attention what changes earths undergo by the oxygen which 

 they abforb by decompofing the fleam of water. I have no 

 doubt that fuch an examination would lead to very important 

 difcoveries. Thefe ideas I fubmit to the knowledge and cri- 

 licifm of the illuftrious French chemifts the editors of the 

 Annales dc Chimie, the fathers of the fcience ; by them it 

 was created. Before them, chemiftry was only a {hapelefs 

 mafs of fa6ls, ill arranged and flill worfe explained. 



IX. Method of dcleB'ing the Vrefence of Sulphur and Arfen'ic 

 in Ore, and of accurately determining the Qua?ititj, By 

 B. G. Sage, Diredor of the frjl School of Mines. 



Ti 



H E torrefa£lion or roafting of a mineral difengages 

 and decompofcs the arfenic and fulphur it contains: but the 

 earth of the metal is calcined, and lays hold of a portion of 

 the acid and the water; which increafes its weight, fo that 

 no juft ellimate can be formed of the proportions of fulphur 

 and arfenic whicli the mineral contains. Befides, thefe two 

 fubftanccs burn fimultaneoufly : torrefaclion, therefore, is not 

 fufficicnt to afford any precifion. 



The diftiliation of two parts of the vitriolic acid with one 

 of the pulverifed mineral, which contains fulphur and arfenic 

 combined with metallic fubftances, furniflies the means of 

 determining w '.th preciiion the quantity of fulphur and arfenic 

 they contain. Tliere firit paffes over fulphureous acid, which 

 .arifes from the decompofuion of the metallic part *, and of 



the 

 f The author here ufts die term metalUfaleurf on which he has the 



follow jntf 



