an increase
in amount to meet the lime deficiency, and a distinct concession in
price is to be expected when a 10-mesh screen is used in testing. At the
same time a careful buyer will use a 60-mesh screen to determine the
percentage that probably has availability for the immediate future. A
coarsely ground article, containing any considerable percentage that
will not pass through a 10-mesh screen, must sell at a price justifying
an application sufficient to meet the need of the soil for a long term
of years, as the greater part has no immediate availability, and only a
heavy application can provide a good supply for immediate need.

_New York State Experience._ A bulletin of the New York agricultural
experiment station, published early in 1917, calls attention to the
rapid increase in demand for ground limestone in New York. Within the
last five years the number of grinding plants within the state had
increased from one to 56, and more than a dozen outside plants are
shipping extensively into the state. The bulletin says: "Farmers who
have had experience with the use of ground limestone are as a rule
satisfied with only a reasonable degree of fineness, and are able to
judge the material by inspection. When limestone is ground so the entire
product will pass a 10-mesh (or 2 mm.) sieve, the greater part of it
will be finer than a 40-mesh (or 1/2 mm.) sieve.... There are now in
operation in this State more than a dozen small portable community
grinders; they are doing much to help solve the ground limestone problem
and their use is rapidly increasing. In the practical operation of these
machines they grind only to medium fineness (2 mm.). To insist upon
extreme fineness is to discourage their use."

This State experiment station is only one of many scientific authorities
approving the use of limestone reduced only to such fineness that it
will pass through a 10-mesh screen, the cost of the grinding being
sufficiently small to permit heavy applications.

CHAPTER X

FRESH BURNED LIME

_An Old Practice._ The beneficial effect of caustic lime on land is
mentioned in some ancient writings. Burning and slaking afforded the
only known method of reducing stone for use in sour soils. Lime in this
form not only is an effective agent for correcting soil acidity, but it
improves the physical condition of tough and intractable clays,
rendering them more friable and easy of tillage. Caustic lime also
renders the organic ma