C 103 3 



ashes of plants ; but in very minute quantities only. 

 When the ashes of plants are reddish brown, they 

 abound in oxides of iron. When black or purple, in 

 oxide of manganesum ; when these colours are mixed 

 they contain both substances. 



The saline compounds contained in plants, or 

 afforded by their incineration, are very various. The 

 sulphuric acid combined with potassa, or sulphate of 

 potassa, is one of the most usual. Common salt is 

 likewise very often found in the ashes of plants ; like- 

 wise phosphate of lime, which is insoluble in water, 

 but soluble in muriatic acid. Compounds of the nitric, 

 muriatic, sulphuric, and phosphoric acids, with alkalies 

 and earths, exist in the sap of many plants, or are af- 

 forded by their evaporation and incineration. The 

 salts of potassa are distinguished from those of soda, 

 by their producing a precipitate in solutions of pla- 

 tina : those of lime are characterized by the cloudiness 

 they occasion in solutions containing oxalic acid ; 

 those of magnesia, by being rendered cloudy by solu- 

 tions of ammonia. Sulphuric acid is detected in salts 

 by the dense white precipitate it forms in solutions of 

 baryta. Muriatic acid by the cloudiness it communi- 

 cates to solution of nitrat of silver ; and when salts 

 contain nitric acid, they produce scintillations by being 

 thrown upon burning coals. 



As no applications have been made of any of the 

 neutral salts, or analogous compounds found in plants, 

 in a separate state, it will be useless to describe them 

 individually. The following tables are given from 



