on as much clean water as before; stir the contents, and continue this process until the water poured off, is as clear as that poured on the earth. What remains in the first employed vase is sand, silicious or calcareous.

"3d. The dirty water, collected in the second vase, will form a deposit, which (after pouring off the wa-ter) must be dried, weighed and calcined. On weighing it after this process, the quantity lost will show the portion of animal and vegetable mould contained in the soil; and,

"4th. This calcined matter must then be carefully pulverised and weighed, as also the first deposit of sand, but without mixing them. To these, apply (separately) sulphuric acid, and what they respectively lose in weight, is the portion of calcareous or aluminous earths contained in them. These last may be separated from the mass by soap lie, which dissolves them."[3]

Here is the light we wanted. In knowing the disease, we find the cure. Clay and sand qualify each other; either of these will correct an excess of lime; and magnesian earth, when saturated with carbonic acid, becomes fertile.

But entirely to alter the constitution of a soil, whether by mechanical or other means, is a work of time, labour and expense, and little adapted to the pecuniary circumstances of farmers in general. Fortunately, a remedy, cheaper, more accessible and less difficult, is found in that great diversity of habits and character, which mark the vegetable races. We shall, therefore, in what remains of this section, indicate the principal of these, as furnishing the basis of all rational agriculture.

1st. Plants have different systems of roots, stems and leaves, and adapt themselves accordingly to different kinds of soils: the Tussilago prefers clay, the Spergula sand; Asparagus will not flourish on a bed of granite nor Musus Islandicus on one of alluvion. It is obvious, that fibrous rooted plants, which occupy only the surface of the earth, can subsist on comparatively stiff and compact soils in which those of the leguminous and cruciform families would perish, from inability to penetrate and divide.

2d. Plans of the same, or of a similar kind, do not follow each other advantageously in the same soil. Every careful observer must have seen how grasses alternate in meadows or pastures, where nature is left to herself. At one time, timothy, at another clover, at a third red-top, and at a fourth blue grass prevails. The same remark applies to forest trees; the original growth of wood, is rarely succeeded by a second of the same kind; pine is followed by oak, oak by chesnut, chesnut by hickory. A young apple tree will not live in a place where an old one has died; even the pear tree does not thrive in succession to an apple tree, but stone fruit will follow either with advantage. "In the Gautinois (says Bosc,) saffron is not resumed but after a lapse of twenty years; and in the Netherlands, flax and colzat require an interval of six years. Peas, when they follow beans, give a lighter crop than when they succeed plants of another family."[4]

3d. Vegetables, whether of the name family or not, having a similar structure of roots, should not succeed each other. It has been observed, that trees suffer considerably by the neighbourhood of sainfoin and lucern, on account of the great depth to which the roots of these plants penetrate—whereas culmiferous grasses do them no harm.

4th. Annual or biennial trefoils, prevent the escape of moisture by evaporation, or filtration, from sandy and arid soils, and should constantly cover them in the absence of other plants;[5] while drying and dividing crops, as beans, cabbages, chickory, &c. &c. are best fitted to correct the faults of stiff and wet clays.

5th. When plants, are cultivated in rows or hills, and the ground between them is thoroughly worked, the earth is kept open, divided and permeable to air, heat and water, and accordingly receives from the atmosphere nearly as much alimentary provision as it gives to the plant. This principle is the basis of the drill husbandry.

6th. All plants permitted to go through the phases of vegetation (and of course to give their seeds) exhaust the ground in a greater or less degree; but if cut green, and before seeding, they take little from the principle of fertility.

7th. Plants are exhausters in proportion to the length of time they occupy the soil. Those of the culmiferous kinds (wheat, rye, &c.) do not ripen under ten months, and during this period, forbid the earth from being stirred: while, on the other hand, leguminous plants occupy it but six months, and permit frequent ploughings. This is one reason why culmiferous crops are greater exhausters than leguminous; another is, that the stems of culmiferous plants become hard and flinty, and their leaves dry and yellow, from the time of flowering till the ripening of the seed—losing their inhaling or absorbing faculties—circulating no juices, and living altogether in their roots, and on aliments exclusively derived from the earth, whereas leguminous or cruciferous plants, as cabbages, turnips, &c. &c. have succulent stems, and broad and porous leaves, and draw their principal nourishment from the atmosphere. The remains of culmiferous crops, also are fewer, and less easily decomposed, than those of the leguminous family.

8th. Meadows, natural and artificial, yield the food necessary to cattle, and, in proportion as these are multiplied, manures are increased and the soil made better. Another circumstance that recommends them is, that so long as they last, they exact but little labour, and leave the whole force of the farmer to be directed to his arable grounds.[6]

9th. Grasses are either fibrous or tap-rooted, or both. The remarks already made in articles 1, 2 and 3, apply also to them. Timothy, red-top, oat-grass and rye-grass, succeed best in stiff, wet soils. Sainfoin does well on soils the most bare, mountainous and arid; lucern and the trefoils, (or clovers,) only attain the perfection of which they are susceptible, in warm, dry, calcareous earth.

10th. The ameliorating quality of tap-rooted plants is supposed to be in proportion to their natural duration; annual clover, (lupinella) has less of this property than biennial, (Dutch clover,) biennial less than sainfoin, and sainfoin less than lucern.

11th. Any green crop, ploughed into the soil, has an effect highly improving; but for this purpose, lupins and buckwheat (cut when in flower) are most proper.

12. Mixed crops (as Indian corn, pumpkins, and peas and oats,) are much and profitably employed, and with less injury to the soil than either corn or oats alone.

SECTION V.

Of Practical Agriculture, and its necessary Instruments.

We begin this part of our subject with a few remarks on the instruments necessary to agriculture, which may be comprised under the well known names of the plough, the harrow, the roller,