ANALYSIS OF SOILS. gj 



confifts wholly of carbonate of lime, it will be rapidly foluble 

 in muriatic acid, with effervefcence ; but if it confift partly of 

 this fubftance, and partly of filiceous matter, the refpective 

 quantities may be afcertained by weighing the refiduum after 

 the action of the acid, which mud be applied till the mixture 

 has acquired a four tafte, and has ceafed to effervefce. This 

 refiduum is the filicious part : it muft be wathed, dried, and 

 heated ftrongly in a crucible; the difference between the weight 

 of it and the weight of the whole, indicates the proportion of 

 calcareous fand. 



IX. Examination of the finely divided Matter of Soils, and Mode 

 of detecting mild Lime and Magnefea. 



The finely divided matter of the foil is ufually very compound The findy di- 

 in its nature; itfometimes contains all the four primitive earths treate( j. 

 of foils, as well as animal and vegetable matter; and to afcer- . 



tain the proportions of thefe with tolerable accuracy, is the raoft 

 difficult part of the fubject. 



The firfl procefs to be performed, in this part of the analytic Muriatic acid 

 is the expofure of the fine matter of the foil to the action of the ™ g " JJfJ' ™' 

 muriatic acid. This fubftance fhould be poured upon the earthy iron, 

 matter in an evaporating bafon, in a quantity equal to twice 

 the weight of the earthy matter; but diluted with double its 

 volume of water. The mixture mould be often ftirred, and 

 fuffered to remain for an hour or an hour and a half before it is 

 examined. 



If any carbonate of lime or of magnefia exift in the foil, 

 they will have been diffolved in this time by the acid, which- 

 fometimes takes up likewife a little oxide of iron ; but very 

 feldom any alumine. jPl 



The fluid mould be patted through a filter; the folid matter Preclp. of iron 



collected, wathed with rain water, dried at a moderate heat, ( lf £ rd f, nt ?. Ly 



... pruff. alkah j 



and weighed. Its lofs will denote the quantity of folid matter 



taken up. The warnings muft be added to the folution, which 

 if not four to the tafte, muft be made fo by the addition of frefh 

 acid, when a little folution of common prufliate of potam muft: 

 be mixed with the whole. If a blue precipitate occurs, it de- 

 notes the prefence of oxide of iron, and the folution of the 

 prufliate muft be dropped in till no farther effect is produced. 

 To afcertain its quantity, it muft be collected in the fame 

 manner as other folid precipitates, and heated red; the refult 



is oxide of iron. 



Into 





