CO i'.LE ACIDS. 



itely precipitates. But citrate ot' ainm. 

 produces no such effect ; yet citrate ot' lime is 

 insoluble in water, as well as the other two cal- 

 careous salts. Citrate of ammonia does not oc- 

 casion a precipitate in nitrate of lead, although 

 citrate of lead is quite insoluble in water. But 

 oxalate and tartrate of ammonia precipitate lead 

 with great energy. This acid is seldom em- 

 ployed by chemists as a reagent, and of course, 

 i- of inferior importance in a chemical point of 

 view. But it exists BIO abundantly in the vege- 

 table kingdom, constituting a portion of so 

 many fruits, that a knowledge of its nature and 

 constitution, constitutes an interesting problem 

 in vegetable physiology. In my experiments to 

 determine the atomic weight of this acid, I was 

 directed by those which Berzelius had published 

 in 1815.* 



*" 9*5 grains of the crystals of citric acid were 

 citric add. dissolved in water, saturated with ammonia, and 

 the solution deprived of all execs* of ammonia 

 by evaporation. ft)*7 grains of dry nitrate of 

 lead were dissolved in another portion of dis- 

 tilled water, and the two solutions were mixed 

 together. No precipitate appearing, and no 

 indication of a double decomposition taking 

 place, the liquid was slowly evaporated to dry- 

 ness. Water being digested upon the dry resi- 



A.. . 9a 



