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the soil, a white precipitate will gradually form in 
the fluid, and the weight of it will indicate the 
proportion. 
Phosphate of lime, if any exist, may be separ- 
ated from the soil after the process for gypsum. 
Muriatic acid must be digested upon the soil, in 
quantity more than sufficient to saturate the soluble 
earths; the solution must be evaporated, and 
water poured upon the solid matter. This fluid 
will dissolve the compounds of earths with the 
muriatic acid, and leave the phosphate of lime 
untouched. It would not fall within- the limits 
assigned to this Lecture to detail any processes 
for the detection of substances which may be 
accidentally mixed with the matters of soils. 
Other earths and metallic oxides are now and then 
found in them, but in quantities too minute to 
bear any relation to fertility or barrenness, and the 
search for them would make the analysis much 
more complicated, without rendering it more useful. 
10. When the examination of a soil is completed, 
the products should be numerically arranged, and 
their quantities added together, and if they nearly 
equal the original quantity of soil, the analysis 
may be considered as accurate. It must, however, 
be noticed, that when phosphate or sulphate of 
lime are discovered by the independent process 
just described (9), a correction must be made for 
the general process, by subtracting a sum equal to 
their weight from the quantity of carbonate of 
lime, obtained by precipitation from the muriatic 
acid. 
In arranging the products, the form should be 
