Page images
PDF
EPUB

§ 25.

It has been demonstrated, in the preceeding part of this Essay, that lime differs not in any of its qualities from chalk, except that it is deprived of its fixed air— which can have no effect on it as a manure; because it again absorbs that fixed air before it has been a few days applied to the foil. After this period, therefore, what was originally lime is now chalk, and must have the same effects upon the soil, in every respecl^ as an equal quantity of chalk, equally spread upon it, would have had.

It is easy, however, for those who attend to the praclice of this gentleman, to account for his partiality for chalk. The quantity of chalk he recommends is twentyfive loads per acre; which, I suppose, may

be be about twelve hundred bushels *. He advises only ten or fifteen bushels of lime. Is it surprising that the effects of these two dressings should be extremely different?

He ventured once to give a field of clay a dressing of sixty bushels of lime—after which he took,

1. wheat, produce 16 bushels,

2. oats, - - 4 quarters,

3. barley, - 5 bushels,

4. clover, - worth nothing.

Hence, says he, the lime has ruined my soil.

The foil was acknowledged to be poor— Instead of sixty, it is doubttul if six hundred bushels would have been sufficient to make it produce good crops under a management so execrable in other respects.

But—

* A load I understand to be a waggon-load— which, I suppose, may contain between five and six quarters.

But—to leave off these ungracious strictures, I now proceed.

§26.

Chalk, as has been often said in the course of this essay, is a pure calcareous earth hastily concreted. Sometimes it is mixed with a small proportion of argillaceous * matter, in which state it approaches to the nature of marie. In either the one or the other of these states, it is employed as a manure in the countries where it abounds.

Chalk differs not from lime in any particular that can affect the farmer, unless it be that lime, by being in the state of a fine powder, admits of being more equally spread upon the ground, and more intimately mixed with the soil, than ckalk; from whence it follows, that a much smaller quantity of

lime

* Clayey. .

lime may be employed successively as a dressing for ground, than could possibly be the case with chalk. *

In order, therefore, to make chalk produce the greatest possible effect upon the soil, it becomes necessary to reduce it into as small piece* as can be done—so that it ought to be an object of great importance to those farmers who have an opportunity of employing this substance, to discover what is the easiest and'least expensive method of reducing it, as soon as possible after it is spread upon the soil, into very small portions.

Chalk is such a porous substance, that, when in its native bed, after long and continued rains, it is found to have imbibed a great deal of moisture by which it as-' sumes a softish feel to the touch.

But if chalk be dug out of the pit, and dried flowly and perfectly by the heat of a summer's sun, its pores become, in some degree, contracted;—it resists, in a great measure, sure, the fresh admission of water, and acquires a much greater degree of hardness, than when it was originally dug from the quarry.

On the contrary, if it be taken from the pit during the wet weather in winter, and exposed to the rains that usually fall at that season, it has never time to dry—its pores remain quite full of water; and, when the frost comes on, that water, in the act of freezing, being greatly expanded, bursts it forcibly asunder, and makes it crumble down into a flimey kind of powder. And, as the pieces that may remain undecomposed continue to absorb more as the rains fall from the heavens, the frosts that may succeed occasion a new dissolution—so that, by these alternate rains and frosts, the whole is in time totally divided, so as to admit of being pretty evenly spread and mixed with the soil.

For

« PreviousContinue »