they would be retained if these substances were not made to enter into combination with lime. Lime has been employed as a fertilizer from a very remote period: both Cato and Pliny attest the use of it by the Roman cultivators. The chemical uses of lime to vegetation may be divided into two parts: first, its direct action on vegetable matter; secondly, its chemical operation on the matters contained in all cultivatable soils. In its direct action as a food, or constituent for plants, its uses are of the greatest importance, for hardly a single plant has yet been analyzed in which the presence of lime has not been detected, in combination with an acid. It is found in the commonly cultivated crops of the farmer in very varying proportions: thus the ashes of the oat plant contain more than five cent. of lime. In two pounds weight of the seeds of wheat are found about 12 grains of carbonate of lime; in the same quantity of rye, about 13–4 grains; in barley, 24–8 grains; 33–75 grains in the oat; and 46–2 in the same quantity of rye straw. It abounds also, with magnesia, in the wood of trees. The ashes of the oak contain about 32 per cent. of earthy carbonates; those from the poplar, 27 per cent.; of the mulberry, 56 per cent. The proportion of lime found in plants varies with the composition of the soil on which they are produced. There are very few soils fit for cultivation from which this earth is entirely absent; and its addition is found by the farmer to promote the fertility of most barren lands. The attraction of lime for the aqueous particles of the atmosphere is considerable, and is, therefore, not without its uses in this respect to vegetation. The chemical action of lime is also very considerable: mixing with the heavy adhesive clays, it renders them much more friable, less liable to be injuriously acted upon by the sun, and much more readily permeable by the gases and vapour of the atmosphere. It renders them—the cultivator tells you—“more easily workable.” And again, the action of lime upon the organic substances always more or less contained in the farmer's soils, is very considerable. This benefit is not merely confined to the vegetable remains in the land, but it extends with equal energy to the dead and the living animal matter with which, in a countless variety of forms, the land is tenanted. There are few substances more destructive to grub-worms, ani-malculæ, etc., than lime; and where these are destroyed by lime, the soil is, as a natural consequence, enriched by their remains. On soils which abound with sulphate of iron—which is commonly the case with those which contain an excess of peat—the action of lime is not only beneficial in decomposing or rendering soluble the mass of inert vegetable remains, but the lime decomposes the sulphate of iron, and, uniting with its sulphuric acid, forms the well-known fertilizer, the sulphate of lime, or gypsum, of commerce.