ANAtTTSIS OF SOILS, £j 



while and tranfparent, it may be confidered as principally 

 faline matter. Nitrate of potafti (nitre) or nitrate of lime, 

 is indicated in this faline matter, by its fcintillating with a 

 burning coal. Sulphate of magnelia may be delected by its 

 bitter tafte; and fulphate of potalh produces no alteration in 

 folution of carbonate of ammoniac, but precipitates folution 

 of muriate of barytes, 



XIII. Mode of detecting Sulphate of Lime (Gypfam) and 

 Phofphate of Lime in Soils. 



Should fulphate of phofphate of lime be fufpecled in the Sulphate of 

 entire foil, the detection of them requires a particular procefs iaie * 

 upon it. /± given weight of it, for in fiance four hundred 

 grains, muft be heated red for half an houi in a crucible, 

 mixed with one-third of powdered charcoal. The mixture 

 muft be boiled for a quarter of an hour, in a half pint of 

 water, and the fluid collected through the filter, and expofed 

 for fome days to the atmofphere in an open veflel. If any 

 foluble quantity of fulphate of lime (gypfum) exifted in the 

 foil, a white precipitate will gradually form in the fluid, and 

 the weight of it will indicate the proportion. 



Phofphate of lime, if any exift, may be feparated from the Phofphate of 

 foil after the procefs for gypfum. Muriatic acid muft be iim * 4 

 digefted upon the foil, in quantity more than fufhcient to 

 faturate the foluble earths ; the folution muft be evaporated, 

 and water poured upon the folid matter. This fluid will dif- 

 folve the compounds of earths with the muriatic acid, and 

 leave the phofphate of lime untouched. 



It would not fall within the limits afligned to this paper, to 

 detail any procefles for the detection of fubftances which may 

 be accidentally mixed with the matters of foils. Manganefe \ 



is now and then found in them, and compounds of the barytic 

 earth ; but thefe bodies appear to bear little relation to fertility 

 or barrennefs, and thefearchfor them would make the analyfis 

 much more complicated without rendering it more ufeful. 



XIV. Statement of Refults and Products, 



When the examination of a foil is compleated, the products Products iia$e!» 



mould be clafled, and their quantities added together, and if 



they nearly equal the original quantity of foil, the analyfis 



may be confidered as accurate. It muft, however, be noticed, 



3 that 



