“One of the most valuable of correctives is lime, which is indispensable to soils lacking limestone, indispensable also to the nutrition of nearly all our cultivated vegetables. It acts in various ways. First, it energetically attacks vegetable substances, decomposing them and converting them into humus. A pile of leaves that would take long months to rot becomes in a short time a mass of humus when mixed with lime. Hence its great utility in fields overgrown with weeds, and in newly cleared land—in short, wherever there are old stumps, piles of leaves, remnants of wood, and patches of heather, which need to be decomposed. With the help of lime all these herbaceous or woody substances are quickly converted into humus, with which the soil becomes enriched to the great advantage of future crops. “In the second place, lime corrects or neutralizes the acidity peculiar to certain soils, as is proved by the following experiment. Let us mix some vinegar, no matter how strong, with a little lime. In a short time the smell and acid taste of the vinegar will have disappeared. Now wherever masses of vegetable refuse, such as leaves, mosses, rushes, old stumps, are undergoing decay, there are produced certain sour-tasting substances or, in other words, acids, which are invariably harmful to agriculture. This generation of acid occurs notably in turfy soils, which have an excessive acidity favorable to the growth of coarse rushes and sedges that are valueless to us, and at the same time this acid is highly injurious to all our cultivated plants. Lime, therefore, which is sure to correct this acidity, works wonders in marshy lands, damp meadows, and turfy soils. We are warned of the need of lime by the appearance of ferns, heather, sedge or reed-grass, rushes, mosses and sphagnei. “Thirdly, when once mixed with the soil, lime speedily resumes the form it wore before passing through the lime-kiln; that is to say, it becomes limestone, but in the shape of fine powder. This return to the limestone condition is brought about by union with the carbonic acid gas coming from the atmosphere or thrown off by the substances decaying in the ground. Under this new form lime continues to play a useful part by supplying the calcareous ingredient to soil that lacked it, and also by preventing the clay from becoming too cohesive, too impervious to air and water. “The addition of lime to the soil should take place at the end of summer, when the ground is dry. Little heaps of quicklime, each containing about twenty kilograms, are placed at intervals of five meters and covered with a few spadefuls of earth. In a short time the moisture in the atmosphere reduces the lime to a fine powder, which is then spread evenly with a shovel and covered with earth—an operation involving no severe labor.