C 147 ] 



The remaining fluid must be boiled for a quarter 

 of an hour, when the magnesia, if any exist, will be 

 precipitated from it, combined with carbonic acid, and 

 its quantity is to be ascertained in the same manner as 

 that of the carbonate of lime. 



If any minute proportion of, alumina should, 

 from peculiar circumstances, be dissolved by the acid, 

 it will be found in the precipitate with the carbonate of 

 lime, and it may be separated from it by boiling it for 

 a few minutes with soap lye, sufficient to cover the 

 solid matter; this substance dissolves alumina, with- 

 out acting upon carbonate of lime. 



Should the finely divided soil be sufficiently cal- 

 careous to effervesce very strongly with acids, a very 

 simple method may be adopted for ascertaining the 

 quantity of carbonate of lime, and one sufficiently ac- 

 curate in all common cases. 



Carbonate of lime, in all its states, contains a de- 

 terminate proportion of carbonic acid, /. e. nearly 43 

 per cent, so that when the quantity of this elastic fluid 

 given out by any soil during the solution of its calcare- 

 ous matter in an acid is known, either in weight or 

 measure, the quantity of carbonate of lime may be 

 easily discovered. 



When the process by diminution of weight is 

 employed, two parts of the acid and one part of the 

 matter of the soil must be weighed in two separate bot- 

 tles, and very slowly mixed together till the efferves- 

 cence ceases; the difference between their weight be- 

 fore and after the experiment, denotes the quantity 

 of carbonic carbonic acid lostj for every four grains 



