ANALYSIS OF WINE. 337 



luble. If the precipitate be washed, still more of the 

 above-named substances are dissolved. 



If to the liquid which has filtered off, basic acetate 

 of lead be added, the precipitate will first contain 

 the insignificant amount of colouring matter which 

 has passed through, and then the non-volatile vege- 

 table acids, the trace of phosphoric acid and chlo- 

 rine, and also a portion of the gum contained in 

 wine. 



If the liquid be again filtered, and ammonia be 

 added, a third precipitate is obtained, containing the 

 sugar and the rest of the gum. 



If this be now put into a filter, and sulphuric acid 

 dropped in, in order to precipitate the lead, and the 

 precipitate then separated, a liquid remains in which 

 organic bodies which had not previously been preci- 

 pitated are found, together with potash, soda, mag- 

 nesia, and lime. 



We have thus three precipitates, the first produced 

 by__sugax of lead, the second by basic acetate of lead, 

 and the third by basic acetate of lead and ammonia. 



After these precipitates have been well washed, 

 they are suspended in water and sulphuretted hydro- 

 gen passed through them, filtered, the liquid warmed, 

 in order to expel the excess of sulphuretted hydrogen, 

 and again filtered. 



Three liquids and three separate amounts of sul- 

 phide of lead are thus obtained, of which the third 

 contains nothing, the second a little colouring matter, 



z 



