1S46.] Analysis of Soils. 223 



arid and water. The water being poured upon the soil first so as 

 to cover it, and the acid then is added, a few drops at a time. 

 Notice whether there is any effervescence in the flask. If so then 

 a carbonate of some base is present, probably carbonate of lime, 

 either as an original ingredient or as the product of combustion 

 of some organic salt of lime. This question can be settled at 

 once by testing some of the unburnt soil in the same manner. If 

 it does not effervesce with acids, then all the lime is in combina- 

 tion with some organic or with nitric acid. This question will 

 be examined farther on, when we speak of the salts in soils. he 

 chlorohydric acid is boiled with the soil for a sufficient length of 

 time to dissolve all the soluble mineral ingredients, generally half 

 an hour suffices to effect the solution. The acid solution is next 

 fdtered through double counterpoised India paper fdters, and all 

 the soil is washed out of the flask with boiling distilled water, 

 and is thrown on the filter. The filter of course is contained in 

 a glass funnel, with its neck inserted in a proper flask to receive 

 the filtered liquid. Wash the filter and the siliceous matter left 

 on it so long as any acid reaction is discovered in testing a drop 

 of the wash water at the neck of the funnel. A strip of blue lit- 

 mus paper is used as the test, and should not be reddened by the 

 wash water. The filters may then be removed, placed on bibu- 

 lous paper in the drying closet and dried. Then the two filters 

 are to be separated and burnt apart, and the outside filter ashes is 

 put in the weight pan, and the inner with its insoluble silicates 

 into the other pan, and the difference of weight is that of the in- 

 soluble silicates. Let us suppose it to be 85 grains; then 6 grains 

 of mineral matter had been dissolved by the acid, and 84 per cent 

 of insoluble silicates remains. The latter is to be laid aside for 

 farther analysis as we shall describe farther on. 



We now return to the soluble mineral matters which we have 

 separated by the filter. This solution is to be treated with a few 

 drops of strong nitric acid, and it is then to be boiled in order to 

 per-oxidize any salt of iron it may contain. Then if, as it usually 

 is, it be very acid with chlorohydric acid, we add pure aqua 

 ammonia in excess, and heat it to simmering, and then filter on 



