C 145 ] 



The water of Hxiviation must be preserved, as it will 

 be found to contain the saline and soluble animal or 

 vegetable matters, if any exist in the soil. 



4. By the process of washing and filtration, the 

 soil is separated into two portions, the most important 

 of which is generally the finely divided matter. A 

 minute analysis of the sand is seldom or never neces- 

 sary, and its nature may be detected in the same man- 

 ner as that of the stones or gravel. It is always either 

 siliceous sand, or calcareous sand, or a mixture of 

 both. If it consist wholly of carbonate of lime, it will 

 be rapidly soluble in muriatic acid, with effervescence ; 

 but if it consist partly of this substance, and partly of 

 siliceous matter, the respective quantities may be as- 

 certained by weighing the residuum after the action of 

 the acid, which must be applied till the mixture has 

 acquired a sour taste, and has ceased to effervesce. 

 This residuum is the siliceous part: it must be washed, 

 dried, and heated strongly in a crucible; the difference 

 between the weight of it and the weight of the whole, 

 indicates the proportion of calcareous sand. 



5. The finely divided matter of the soil is usually 

 very compound in its nature; it sometimes contains all 

 the f6ur primitive earths of soils, as well as animal and 

 vegetable matter; and to ascertain the proportions of 

 these with tolerable accuracy, is the most difficult part 

 of the subject. 



The first process to be performed, in this part of 

 the analysis, is the exposure of the fine matter of the 

 soil to the action of muriatic acid. This substance 

 should be poured upon the earthy matter in an eva- 



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