354 COMBINATION OP MKRCURY 



with the liquor, whenever it is no longer affected 

 by the folution of common fait. In this man- 

 ner a white powder is "precipitated, which ac- 

 cording to Junker* is equal to half the quantity 

 of the mercury employed in the folution. The 

 authors of the Edinburgh pharmacopoeia direct 

 the white mercurial precipitate to be prepared 

 by diflblving corrofive fublimate in water and 

 adding fpirit of fal ammoniac to the folution. 

 The London phtrmacopoeia, following the ex- 

 ample of Lemeryf, order corrofive mercury 

 and nitre to be feparately diflblved in four times 

 their quantity of waterf, the folution to be fil- 

 tered, and fixed alkali to be afterwards added 

 to it. By this method, a white powder is pro- 

 cured equal to three-fourths of the weight of the 

 corrofive mercury $. Sa! ammoniac does not 

 render corroftvc mercury milder only, but it 

 gives a whiter colour likewife to the precipi- 

 tate || . If the precipitation is made with urine, 

 and the fpirit of fal ammoniac u afterwards 

 poured upon it, the black mercurial precipitate 

 of Lemery is the produce of that mixture. 



From what we have already faid it mull be e- 



vident, 



* JL. c. 



j- Coura de Chcmic. 



t Which however cannot be done, v.'.ucf* fal ammoniac is 

 aJJo'. 



^Dcfli-, Laboratory laid open. 

 !| Hucrnc Tent, Chynru T. II. 



