On the Analysis of Soils. 33 



ferrescence ceases in it, and till its taste and smell indicate 

 a considerable excess of alkaline salt. 



The precipitate that tails down is carbonate of lime; it 

 must be collected oa the filler, aiul dried at a heat below 

 that of redness. 



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 alumlne should, from pecu- 

 liar 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 for a few minutes with soap 

 lye, sufficient to cover the solid matter. This substance 

 dissolves alumine, without acting upon carbonate of lime. 



Should the finely divided soil be sufficiently calcareous to 

 effervesce very strongly with acids, a very simple method 

 may be adopted for ascertaining the quantity of carbonate 

 of lime, and one sufficiently accurate in all common cases. 



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

 nate proportion of carbonic acid, i. e. about 45 per cent.; so 

 that when the quantity of this elastic fluid, given out by 

 any soil during the solution of its calcareous matter in an 

 ieid, is known, cither in weight or measure, the quantity of 

 carbonate of lime may be easilv 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 bottles, and very slowly 

 mixed together till the effervescence ceases ; the difference 

 between their weight before and after the experiment de- 

 notes the quantity of carbonic acid lost; for every four 

 grains and a half of which, ten grains of carbonate of lime 

 must be estimated. 



The best method of collecting the carbonic acid, so as to 

 discover its volume, is bv the pncimiatic apparatus, the 

 construction and application of which arc described at the 

 end of this paper. The estimation is, for every ounce mea- 

 sure of carbonic acid, two grains of carbonate of lime, 



X. Mode of ascertaining the Quant if 1/ f)f insoluble finely 

 divided Anhiud and t'^egefubte Matter. 



After the fine matter of the soil has been acted upon by 

 muriatic acid, tiie next process is to ascertain the quantity 

 of finely divided insoluble animal and vegetable matter that 

 it contains. 



V'oL 23. No. 89. 0(7. 1805. C T\\\s 



