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CHAPTER II

Formula for manual examinations which will lead to
a correct judgment of the distinctive qualities of spe-
CIAL soils.—Manner in which samples of soil must be taken for
analysis—examination of the mechanical texture of the soil—de-
termination of the quantity of Quartz-sand, and undecomposed
fragments of rocks—of the quantity of Cement—of the character
of the rocks—of the water-retaining power of the Cement—of the
physical state of the Cement after drying—of the absorbent powers
of the Cement for gases, and moisture, &c.—Examination of the
directly nourishing properties of the soil—determination of Phos-
phoric acid—of Sulphuric acid—of Chloride—of Lime and Mag-
nesia—of Silicic acid. Potash and Soda.

We have tried in the preceding chapter to collect and exhibit
general facts for a thorough understanding of the functions of soils,
so far as they relate to the wants of plants; all that remains for
this final chapter, is to give such a formula for manual examina-
tions as will lead to a correct judgment of the quality of special
soils. The method in which these examinations may be conducted,
is distinctly dictated by our preceding considerations; we there-
fore have to act here in accordance with them; avoiding elaborate
analyses, which, notwithstanding their troublesome performance,
have shown themselves to be not of the greatest practical utility.

Before commencing the analysis of a soil, it is first necessary to
observe that the sample was taken in the following manner:

With a clean spade a hole should be dug to the depth of the
surface soil; and a slice of uniform thickness (about one inch) then
be taken from the top to the bottom of the hole. This operation
should be repeated in three or four different places on the same
kind of soil; the different specimens thus obtained should then be
mixed together, and about two lbs, of the mixture be put in a clean
bag for analysis. Specimens of the subsoil should he taken in the
same manner as those of the surface soil, special care being taken
to prevent any mixture of the surface soil with it.

If the specimen of soil is not properly taken in the above man-
man, its analysis may prove nothing when done.

It is, secondly, necessary that the specimen is labeled with the
name of the owner of the soil, and the State and county from which
it was taken.

Thirdly and finally, should the specimen be accompanied by a
note in which information is given, as to the location of the soil;