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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 com- 

 pounds 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 barren- 

 ness, and the search for them would make analysis 

 much more complicated without rendering it more 

 useful. 



10. When the examination of a soil is comple- 

 ted, 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 disco- 

 vered 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 precipita- 

 tion from the muriatic acid. 



In arranging the products, the form should be in 

 the order of the experiments by which they were pro- 

 cured. 



Thus, I obtained from 400 grains of a good sili- 

 ceous sandy soil from a hop garden near Tunbridge, 

 Kent, 



