learn whether their
soils are now acid. Practical farmers may judge by the character of the
vegetation and not fail to be right nine times out of ten. Where land
has drainage, and a fairly good amount of available fertility, as
evidenced by growths of grass, a failure of red clover leads
immediately to a strong suspicion that lime is lacking. If alsike
clover grows more readily than the red clover, the probability of
acidity grows stronger because the alsike can thrive under more acid
soil conditions than can the red. Acid soils favor red-top grass rather
than timothy. Sorrel is a weed that thrives in both alkaline and acid
soils, and its presence would not be an index if it could stand
competition with clover in an alkaline soil. The clover can crowd it
out if the ground is not too badly infested with seed, and even then
the sorrel must finally give way. Where sorrel and plantain cover the
ground that has been seeded to clover and grass, the evidence is strong
that the soil conditions are unfriendly to the better plants on account
of a lime deficiency. The experienced farmer who notes the inclination
of his soil to favor alsike clover, red-top, sorrel, and plantain
should infer that lime is lacking. If doubt continues, he should make a
test.

The Litmus-paper Test.--A test of fair reliability may be made with
litmus paper. A package of blue litmus paper can be bought for a few
cents at any drug store. This paper will turn pink when brought into
contact with an acid, and will return to a blue if placed in
lime-water. A drop of vinegar on a sheet of the paper will bring an
immediate change to pink. If the pink sheet be placed in lime-water,
the effect of the lime in correcting the acidity will be evidenced by
the return in color to blue.

To test the soil, a sample of it may be put into a basin and moistened
with rain-water. Several sheets of the blue litmus paper should be
buried in the mud, care being used that the hands are clean and dry.
When one sheet is removed within a few seconds and rinsed with
rain-water, if any pink shows, there is free acid present. Another
sheet should be taken out in five minutes. The rapidity with which the
color changes, and the intensity of the color, are indicative of the
degree of acidity, and aid the judgment in determining how much lime
should be used. If a sheet of the paper retains its blue color in the
soil for twenty minutes, there probably is no lime deficiency. The test
shou