164 ESSAY XI. 



smell, but also from the remaining insoluble black powder, 

 it is necessary to add more nitre; and instead of muriatic 

 acid, which is dearer, a mixture of diluted vitriolic acid and 

 common salt should be poured upon it, with which it is 

 afterwards to be digested. Thus a real butter of antimony 

 is obtained, from which, when diluted with water, the pulvis 

 algarothi is precipitated. The salts contained in this anti- 

 monial solution, viz. Glauber's salt and vitriolated tartar, 

 remain behind in the water, and do not in the least change 

 the precipitate. 



The process is therefore the following : Take of powdered 

 crude antimony 1 lb., powdered nitre 1J lb., which, after 

 being well dried and mixed, are to be detonated in an iron 

 mortar. The hepar obtained in this manner is to be 

 powdered, and 1 lb. of it to be put into a glass vessel, on 

 which first a mixture of 3 lb. of water and 15 oz. of vitriolic 

 acid is to be poured, and afterwards 15 oz. of powdered 

 common salt are to be added ; the glass vessel is then to be 

 put in a sand-bath, and kept in digestion for twelve hours, 

 during which period the mass is to be constantly stirred. 

 The solution when cool is to be strained through linen. 

 Upon the residuum one-third of the above-mentioned men- 

 struum is to be poured, the mixture digested and strained. 

 From this solution, when it is diluted with boiling water, 

 the pulvis algarothi precipitates, which is to be well edul- 

 corated and dried. 



