On the ^null/sis of Soils. 35 



• Should any magnesia and lime have escaped solution in. 

 •the muriatic acid, they will be found in the sulphuric acid: 

 this, however, is scarcely ever the case; but the process for 

 detecting them, and asccrtainlns! theirnuantiues, is the same 

 m both mstanccs. 



The method of an?.lysis by sulphuric acid is sufficiently 

 precise for all usual experiments ; but if very great accuracy 

 be an object, dry carbonate of potash must be employed as 

 theagent,andtheresiduum of the incineration must be heat- 

 ed red for half an hour, with four times its weight of this 

 substance, in a crucible of silver, or of well baked porce- 

 lain. The mass obtained must be dissolved in muriatic 

 acid, and the solution evaporated till it is nearly solid ; 

 distilled wa^er must then be added, by which the oxide of 

 iron and all the earths, .except silex, will be dissolved in 

 conibmation as muriates. The silex, after the usual pro- 

 cess of lixiviation, must be heated red ; the other substances 

 may be separated in the same manner as from the muriatic 

 and sulphuric solutions. 



This process is the one usually employed by chemical 

 philosophers for the analysis of stones. 



XII. MofJe of discovering soluhle Animal and Vegetahle 



JMatter, laicl Saline Matter. 



If any saline matter, or soluble vegetable or animal mat- 

 ter, is suspected in the soil, it will be found in the water of 

 lixiviation used for separating the sand. 



This water must be evaporated to dryness in an appro- 

 priate dish, at a heat below its boiling point. 



If the solid matter obtained is of a brown colour and in- 

 flammable, it mav be considered as partly vegetable extract.. 

 If its smell, when exposed to heat, be strong and foetid, it 

 contains animal mucilaginoua or gelatinous substance; if 

 it be white and transparent, it may be considered as prin- 

 cipally saline matter. Nitrate of potash (nitre), or nitrate 

 of lime, is indicated in this saline matter, by its scintillating 

 with a burning coal. Sulphate of magnesia may be de- 

 tected by its bitter taste ; and-sulphate of potash produces 

 no alteration in solution of carbonate of ammonia, but 

 precipitates solution of muriate of barytcs. 



XIII. Mode of detecting Sull)hate of Lime {Gijpsnni) and 



Phosphnte of Lime in Soils. 

 Should sulphate or phosphate of lime be suspected ia 

 ihQ entire boil, the detcMion of thenj requires a particular 

 (' •_> proces* 



