222 Aftim of Muriatic Add on Siher. [Book VL 



Into the nitrous folution, feize the (ilver, and forming 

 a. compound not equally folnble produce a precipita- 

 tion. The neutral falts, containing vitriolic or mu- 

 riatic acid, have the fame effect. This difference of 

 affinity between die acids and filver is the foundation 

 of a procefs for obtaining the nitrous acid in a ftate of 

 great purity. The folfltion of filver in nitrous acid 

 is poured into the impure nitrous acid till no more 

 precipitate is formed. The muriatic or vitriolic acids- 

 contained in the mixture are thus carried to the bot- 

 tom by their union with the filver. The acid is then 

 decanted and diftilled to free it from the fmall quantity 

 of fait of filver which it may ftill contain. 



Notwithftanding the muriatic acid has the ftrongeft 

 affinity with filver of all the acids, it is neverthelefs 

 incapable of dilTolving it unlefs the metal is in a cal- 

 cined ftate, or itfelf fuperoxygenated. The common 

 method of effecting this union is to add to the folution 

 of filver, in the nitrous acid, any faline fubftance which 

 contains the muriatic acid ; it is no matter to what the 

 acid is joined, whether alkali, earth, or metal ; it im- 

 mediately feizes the filver, and leaves the other matter 

 to unite with the nitrous acid. Common fait is gene- 

 rally ufcd, and the white precipitate, which is imme- 

 diately formed, has the appearance of a coagulum. 

 The compound thus made is fo infoluble in water, 

 that there cannot be a nicer tefl of the prefence of the 

 muriatic acid, or common fait, in waters, than the ni- 

 trous folution of filver ; for if the moft minute quantity 

 of either are prefent a precipitation is produced. 



This. compound has many other qualities befides 

 infolubility in water. If we collect it, and wafh off 

 the faline matter, it appears as a fine powder, and, 

 when heated to a fufficient degree, melts into a fub- 

 ftance of fome tranfparency. From its tranfparency, 



flexibility 



