The utility of lime as manure consists in loosening the tenacious nature of some soils; rendering them more friable and receptive of vegetable fibres: it especially facilitates the dissolution and putrefaction of animal and vegetable substances, which are thus more readily received and circulated in the growing plant; and it has the power of acquiring and long retaining moisture; thus rendering a soil cool and nutritive to the plants that vegetate in it. The power that lime has of absorbing moisture will be better understood, when we say, that one hundred weight will, in five or six days, when fresh, absorb five pounds of water, and that it will retain in the shape of powder, when slackened, or loosened, as is commonly said, nearly one-fourth of its weight.[2] That lime rehardens after being made soft, as in mortar, is owing to the power which it has of acquiring carbonic acid—the fixed air of Dr. Black—from the atmosphere; when the stone is burned, it loses this principle, but re-absorbs it, though slowly, yet in time, and it thus becomes as hard as stone again: we unite it with sand to promote the crystallization and hardening. The utility of lime in various arts, agriculture, manufactories, and medicine, is very extensive, and in many cases indispensable; and the abundance of it spread through the world seems designed as a particular provision of Providence for the various ends of creation. Lime, and siliceous substances, compose a very large portion of the dense matter of our earth; the shells of marine animals contain it abundantly; our bones have eighty parts in one hundred of it; the egg-shells of birds above nine parts in ten—during incubation, it is received by the embryo of the bird, indurating the cartilages, and forming the bones. But the existence and origin of limestone are pre- eminent amongst the wonders of creation; nor should we have been able, rationally, to account for the great diffusion of this substance throughout the globe, however we might have conjectured the formation, without the Mosaical revelation. It may startle, perhaps, the belief of some, who have never considered the subject, to assert what is apparently a fact, that a considerable portion of those prodigious cliffs of chalk and calcareous stone, that in many places control the advance of the ocean, protrude in rocks through its waters, or incrust such large portions of the globe, are of animal origin—the exuviæ of marine substances, or the labors of minute insects, which once inhabited the deep. In this conclusion now chemists and philosophers seem in great measure to coincide. Fourcroy observed, forty years ago, that “it could not be denied, that the strata of calcareous matter, which constitute, as it were, the bark or external covering of our globe, in a great part of its extent, are owing to the remains of the skeletons of sea animals, more or less broken down by the waters; that these beds have been