C 



porating bason, in a quantity equal to twice the weight 

 of the earthy matter; but diluted with double its volume 

 of water. The mixture should be often stirred, and 

 suffered to remain for an hour, or an hour and a half, 

 before it is examined. 



If any carbonate of lime or of magnesia exist in 

 the soil, they will have been dissolved in this time by 

 the acid, which sometimes takes up likewise a little 

 oxide of iron; but very seldom any alumina. 



The fluid should be passed through a filtre; the 

 solid matter collected, washed with rain water, dried 

 at a moderate heat, and weighed. Its loss will denote 

 the quantity of solid matter taken up. The washings 

 must be added to the solution, which if not sour to the 

 taste, must be made so by the addition of fresh acid, 

 when a little solution of prussiate of potassa and iron 

 must be mixed with the whole. If a blue precipitate 

 Occurs, it denotes the presence of oxide of iron, and 

 the solution of the prussiate must be dropped in till 

 no farther effect is produced. To ascertain its quan- 

 tity, it must be collected in the same manner as other 

 solid precipitates, and heated red; the result is oxide 

 of iron, which may be mixed with a little oxide of 

 manganesum. 



Into the fluid freed from oxide of iron, a solu- 

 tion of neutralized carbonate of potash must be pour- 

 ed till all effervescence ceases in it, and till its taste and 

 smell indicate a considerable excess of alkaline salt. 



The precipitate that falls down is carbonate of 

 lime; it must be collected on the filtre, and dried at a 

 heat below that of redness. 



