The only ones that need be concerned with the question of lime for soils are those who cannot secure good growths of the clovers and other legumes. Putting aside past experience, they should 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 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. [Illustration: Red clover on limed and unlimed land.]