1839.] 



On Chemical Tests. 



303 



when a little water is poured upon it. Solution of barytes in water 

 has a caustic taste; and turns reddened litmus paper blue. Pure bary- 

 tes does not fuse at a red heat. The following tests discover barytes, 

 as well as its salts, see also 36. 



•ecipi- 



Hydrqfluosilicic acid ...... { tate which is almost insoluble in free nm- 



' itic or nitric acid. 



A voluminous precipitate which al- 



Piire caustic potash ^ most disappears on adding a quantity of 



r ater. 



Caustic ammonia No precipitate. 



Carbonate of potash \ A , . L . • , , , • 



Carbonate of ammonia \ A w I u J. e P?wprtate soluble in nitric 



Neutral phosphate of soda / 0r mumllc acid 



c , 7 .7 7 f A white precipitate in very dilute so- 



Sulphuric acid produces ... ,\ , . * . K *: , 



" r ( lutions ; it is not soluble id acids. 



( After some time a crystalline pn 



ilicic acid I tate which is almost insoluble infre< 



(riatic or nitric acid. 



{» 

 } 



Oxalic acid f No P reci P itate - But lf the solution be 



Binoxalate of potash ) + st ™ng and ammouia be added, a precipi- 



J r tate occurs. 



Hydrosulphuret of ammonia - } 



Prussiate of potash >No precipitate. 



Red prussiate of poiash J 



a. To detect the presence of barytes in sulphate of barytes, a portion 

 is boiled in a solution of carbonate of potash or soda and filtered. The 

 insoluble remainder is treated with muriatic acid, the solution is filter- 

 ed, and then tested with dilute sulphuric acid which produces a preci- 

 pitate. The sulphate of strontian is insoluble in acid?. The muriatic 

 solution, supposing both baryta and strontian to be present may also^be 

 diluted with water, filtered, and hydrofluosilicic acid be added : the 

 barytes will be precipitated as shewn above; but the strontian will 

 not be affected. By this test sulphate of barytes may be discriminated 

 from sulphate of strontian, see 40 d, 115 b, d, c. 



b. Baryta is precipitated white by phosphates and oxalates (see the 

 test, oxalic acid in this article) ; pale lemon yellow by chromatcs, and 

 white by carbonates, see 40 lu 



c. Barytes, strontites, lime, and magnesia are found always combined 

 with acids, which are generally the carbonic, sulphuric, fluoric, boracic 

 and phosphoric. 



40. BARYTA, solution of ; and the acetate ; muriate; and nitrate 

 of barytes. These four tests act alike namely detecting sulphuric acid, 

 either free or in combination ; and also carbonic acid. They produce a 

 white precipitate in either case; but the sulphuric precipitate is iuso- 



