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The Litmus-paper Test

Categories: THE NEED OF LIME

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 a
idity 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

should be made with samples of soil from various parts of the field,

and they should be taken beneath the surface. One just criticism of

this test is that while no acidity may be shown, the lime content may

be too low for safety.



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