e capacity for destruction of acids.

_Agricultural Lime._ This variable product should not be bought unless
actual composition is known, or the cost is as low as that of pulverized
limestone, and even then it may be a bad purchase, the methods of the
manufacturer being the determining factor. If such lime is chiefly a
dumping place for low-grade stone and forkings, it has small
agricultural value.

_Land Plaster._ The soil wants lime in carbonate form. The oxide and
hydrate change to carbonate, and therefore are good. Land plaster is a
sulphate, and its tendency is to make a soil sour. It should not be
considered as a means of correcting soil acidity.

_Basic Slag._ The amount of effective lime in basic slag, as made by
modern methods, is so small that its value is nearly negligible. Basic
slag is a good source of phosphorus, and in addition has a tendency
toward correction of soil acidity, but such tendency has little cash
value for land that requires a considerable dressing of lime to furnish
a base with which soil acids may combine.

An expression of opinion was obtained recently from some leading soil
chemists of this country, and upon such expression we base the estimate
that when pulverized limestone costs three dollars a ton, the value of
the lime in a ton of basic slag should not be placed higher than 50
cents, and some chemists believe that the lime content is entirely
negligible as an agent in soil amendment.

_Lime in Other Fertilizers._ The demand for lime is leading some men to
state a lime content for their goods that is designed to mislead. Such
lime is not in a form to combine with soil acids, and is as valueless as
the very large amount of lime in acid soils that is in compounds having
no power to affect free acids.

CHAPTER XVI

METHODS OF APPLICATION

_A Controlling Principle._ The chief purpose of liming land is to
provide a base with which acid may combine, so that the soil may be
friendly to plant life. Lime has little power to distribute itself
through a soil, and harmful acid may remain only a few inches distant
from the point where lime has been placed. In a general way, the
tendency of lime is downward, especially when the application at the
surface is heavy. Economical use demands even distribution through the
soil so that a sufficient amount is in every part. Means to that end are
good means of distribution.

_Spreading on Grass._ Where lime is burned on the farm, and litt