Page images
PDF
EPUB

dergo, they have a continual tendency to return to their original state; and, to shew what I mean, one example may be sufficient. Of these earthy substances, one of the most serviceable to man, and consequently one of the best known, is lime, which, in its natural state, is little better than a positive caput mortuum, and of no use either as a manure, or for the purposes of building, until it has passed through the kiln; but, after it has been calcined, and the fixed air, or carbonic acid gas, is expelled by the operation of fire, it becomes of the greatest service to the farmer especially, by assisting the progress of vegetation; which assistance, though seldom understood by the ignorant farmer, is per formed by the action of its return to its former or original state, which commences immediately on its re-exposure to the influence of atmospherical air, from which it again imbibes what has been lost or ex pelled in the kiln; the reabsorption being more or less rapid according to the aspect

of the situation, and the nature of the soil upon which it is laid.

This remarkable property of lime, which is also possessed by some other mineral substances, is either not sufficiently known or attended to by those who are most nearly concerned with its use. The common saying of farmers, that certain fields, or parcels of land, hold this species of manure better than others; or, in other words, that they continue longer to be benefited by its application, originates in the effects of this property. The return of prepared lime to its original state, or its reabsorption of the fixed air which has been expelled, being accelerated or retarded according to the degree of moisture in the situation where it is placed, and its exposure to the solar heat. Thus, though burned lime is highly and very quickly beneficial in cold, wet, and mossy ground, by absorbing the redundant moisture of such a situation, and giving warmth, vigour, and nourishment to the plants with which it has contact; yet

its useful properties will there soon be lost, and it will become a burthen, instead of an improvement, to the soil.

It is on account of this property that lime should not be used as a manure for any long continuance on the same soil, without being mixed with other fertilizing substances. In some parts of the north, and north-western, parts of England, it is much used for grass land; and I am acquainted with several instances where it had the effect, by long use, of rendering very fertile land absolutely barren; by forming a hard, thick, impenetrable crust of indurated, stony, matter on the surface it was intended to fertilize; converting it, in fact, into a mass of real and genuine lime-stone incapable of affording nourishment to a single blade of grass.

In alluding to those continual changes and new combinations of matter which are every where taking place on the surface of this globe, and to which we, ourselves, are liable; my design has been rather to awaken or stimulate a spirit of inquiry into these mysterious and important subjects, which

so particularly belong to the province of the enlightened Naturalist, than to furnish any new or extraordinary facts from my own observation. In this field of inquiry, which is unbounded, the most important results, to the happiness, knowledge, and best interests of mankind, may be obtained.

CHAP. XII.

Conclusion, and Recapitulation.

THE man who surveys the vast field of Nature with an eye of true philosophical inquiry;-who devotes a portion of his time to the study of the principles which in fluence, or govern, the motions of animated beings, however minute they may be, will not only derive infinite pleasure from the pursuit; but he will gain the only means of discovering the object and utility of their creation. And, as he journies along from one gradation of knowledge to another, he will become more and more intimate with the designs, and gain a more comprehensive view, of that wonderful and illimitable Power which hath organized the universe, for purposes with which, in the fulness of time, the wise and the virtuous will, doubtless, be made acquainted; though it may

« PreviousContinue »