298 VINEGAR, CIDER, AND FRUIT-WINES. 



light ; it is dissolved with difficulty in cold water, requiring 33 

 parts at the ordinary temperature. It is partially decomposed 

 by boiling water into acid and basic salts of both oxides and me- 

 tallic mercury. It is used in pharmacy. 



Mercuric acetate. Dissolve red oxide of mercury in concen- 

 trated acetic acid with a gentle heat and evaporate to dry ness, or 

 partially to crystallization, or by spontaneous evaporation. By 

 the first process, it is a white saline mass ; by the second, it forms 

 crystalline scales ; and by the third, four-sided plates, which are 

 partly transparent, partly pearly and translucent ; anhydrous, of 

 a nauseous metallic taste, fusible without decomposition, solidify- 

 ing to a granular mass, but its point of decomposition is near 

 that of fusion. It dissolves in 4 parts of water at 50 F., in 2.75 

 at 66.2 F., and in 1 at 212 F., but by boiling it is partly de- 

 composed, with separation of red oxide ; even in the air its solu- 

 tion suffers the latter change and contains a basic salt. With 

 free acetic acid it is not decomposed ; 1 00 parts of alcohol dis- 

 solve 5-| of this salt, and this solution behaves like the aqueous 

 one. It generally contains, except when carefully crystallized, 

 some mercurous oxide. 



Silver acetate. This salt is obtained by precipitating a concen- 

 trated solution of silver nitrate with a concentrated solution of 

 sodium acetate. It forms a white crystalline precipitate. It dis- 

 solves in about 100 parts of cold, but readily in hot water, and 

 only sparingly in alcohol. On exposure to light it acquires a 

 dark color, being partially reduced. On heating, it yields acetic 

 acid, metallic silver remaining behind. 



If the salt be heated with bisulphide of carbon in a closed 

 glass tube to 329 F., silver sulphide, carbonic acid, and anhy- 

 drous acetic acid are formed (Broughton). 



On treating the dry salt with iodine, lively decomposition takes 

 place, whereby silver iodide, some metallic silver, and coal re- 

 main behind, while methyl oxide, acetic acid, acetylene, and hy- 

 drogpn appear. With iodine a solution of this salt yields acetic 

 acid, silver iodide, and iodate of silver (Birnbaum). 



