than formerly. Let them remain in the ground covered with haulm or litter till they are wanted for setting; and, if no frost touches them afterwards, they will be free from the disease.

XIII. This writer says, the red potatoe was as generally planted as the winter white and the Lincolnshire kidney are now. The first, being a later potatoe, did not sprout so early as the others. The white sprout very early, and therefore should first be moved out of the place where they have been preserved in winter. Instead of that, they often remain till their roots and sprouts are matted together. On separating them, the sprouts are generally rubbed off, and they are laid by till the ground is ready; during which interval they sprout again; but these second sprouts, being weak and languid, shrink, sicken, and die; and the fruit at the roots will be small, hard, ill-shaped, and of a brown colour. Now, if pulling off the sprouts once or more, before the sets are put in the ground, be the cause (as he believes it is) of the curled disease, an easy remedy is at hand. When the potatoes intended for sets are dug up, lay them in a west aspect as dry as possible; in such a situation they will not sprout so soon. The best time for removing most sorts is the first fine day after the 24th of February. Cut them into sets, and let them remain covered with dry sand till the ground is prepared, which should be a winter fallow. Lay the sets in without breaking off any of the sprouts, for the second will not be so vigorous. This accounts for one sprout out of three from the same set being curled. The two stems not curled rose from two later eyes, and were first sprouts. The sprout curled was a second, the first having been rubbed off.

XIV. This writer says, that, last spring, one of his neighbours cut and set, by drilling, some loads of the largest potatoes he could procure; and more than half of them proved curled. Being a few sets short of the quantity wanted, he planted some very small potatoes which he had laid by for the pigs. These being fully ripe and solid, there was not a curled plant among them. He thinks the others being curled was owing to their not being fully ripe. A crop of potatoes, set in rows on ground that had borne a crop of them the preceding year, were mostly curled; but many plants came up from seed left in the ground the former season, and there was not a curled one among them.

XV. Of late years, this writer says, great improvements have been made in setting potatoes and cutting the sets. The ground is dressed cleaner and dunged stronger. Many people, in drilling, wrap up the sets entirely in the dung; by which means, though their potatoes are larger, the disease seems to be increased. They also cut their sets out of the richest and largest potatoes, which is perhaps another cause of this evil. In cold countries, where they set their own seed, which has grown on poor land, with less dung, they have no curled plants. On the contrary, when they bought rich and large potatoes for seed, they have been curled in great quantities. He believes the richness and largeness of the seed to be the cause of the evil; for he does not

remember to have seen a curled stem which did not spring from a set of a large potatoe.

XVI. This writer apprehends the curled disease in potatoes to proceed from a defect in the planta seminalis, or seed-plant; and from comparing curled ones with others, there appeared to be a want of, or inability in the powers of expanding or unfolding the parts of the former; which, from this defect, forms shrivelled, starved, curled stems. On examining some of the sets at the time of getting the crop, he found them hard and undecayed; so hard, indeed, that some of them would not be soft with long boiling. Some have thought that the fermentation is occasioned by too great quantities being heaped together; but this writer has seen an instance, wherein a single potatoe, preserved by itself, when set, produced stems of the curled kind. He thinks the disease is occasioned by the potatoes being taken from the ground before the stamen, or miniature plant, is properly matured and ripened. For the potatoe, being a native of a warm climate, has there more sun, and a longer continuance in the ground, than in its exotic state; consequently, it has not the same natural causes to mature the seed-plant as in its native state. We ought, therefore, to give all the opportunities our climate will admit for nature to complete her work, and fit the stamen for the next state of vegetation, especially in those intended for seed. But if the potatoe be taken up before the seed plant be fully matured, or the air and sap vessels have acquired a proper degree of firmness or hardness, it must, when thus robbed of further nutrition, shrivel up; and when the vessels, in this immature state, come to act again in the second state of vegetation, they may produce plants which are curled. Before the present mode of setting them took place, people covered them, while in the ground, with straw, to protect them from frost. If it be asked, why one set produces both curled and smooth stems? he answers, we suppose every eye to contain a planta seminalis; that all the embryos or seed plants, contained in one potatoe, are nourished by one root; that, as in ears of corn, some of these seed plants may be nourished before others. One of his neighbours, last year, set two rows of potatoes, which proving all curled, he did not take them up; and this year there is not a curled one among them. Such potatoes, therefore, as are designed for seed, should be preserved as long in the ground as possible.

XVII. This writer advises such sets to be planted as grow in moss land; and, he says, there will not be a single curled one the first year. This is affirmed by the inhabitants of two townships, where they raise amazing quantities. A medical gentleman sowed the one year two bushels of sets from one of the above places; and had not one curled; but on sowing them again the following year he had a few.

65. Although there seems to be a diversity of opinions among the above writers, occasioned by the different appearances of their crops, and respecting the means proper to prevent or cure the disease, the following general propositions may be fairly drawn from the whole: 1. That some

kinds of potatoes are (cæteris paribus) more liable to be affected by the disease than the rest; and that the old red, the golden dun, and the long dun, are the most free from it. 2. That the disease is occasioned by one or more of the following causes, either singly or combined: First, by frost, either before or after the sets are planted: Second, From planting sets out of large unripe potatoes: Third, From planting too near the surface, and in old worn-out ground: Fourth, From the first shoots of the sets being broken off before planting; whence there is an incapacity in the planta seminalis to send forth others sufficiently vigorous to expand so fully as they ought. 3. That the most successful methods of preventing the disease are, cutting the sets from smooth middle-sized potatoes, that were fully ripe, and had been kept dry after they were taken out of the ground; and, without rubbing off their first shoots, planting them pretty deep in fresh earth, with a mixture of quicklime, or on lime-stone land.

66. A correspondent of the Bath Society is convinced, that, whatever may be its cause, the fault itself is inherent in the seed; and has communicated the following method of avoiding it: "I made a hot bed in the following manner, which method I have used ever since: I laid horse dung, &c. as in making hot beds, about eighteen inches thick; over which I spread a layer of fine rich mould about four or five inches thick; upon the top of this I laid, in different divisions, a certain number of potatoes of various sorts, some of my own growth, and others brought from different parts, and covered these lightly over with more mould; they soon came up. I then observed which was freest from the blight or curl; for if there were not more than one defective in forty or fifty, I concluded I might set of that sort with safety. This method I have now practised near twelve years, and never lost my crop, or any part thereof worth mentioning; whilst my neighbours, who followed the old method, were frequently disappointed in their crops; and to the best of my knowledge, all those of my neighbours who have of late been persuaded to take the trouble of using the same means as myself, have never failed of success in one instance; nor do I ever think it will fail, if duly attended to; the fault being some hidden cause in the seed, unknown at present, and I believe incurable by any means, at least which have yet come to my knowledge. My reason for planting my hot bed so soon is, that if the frost hinders the first experiment, or they all prove bad, I may have time to make a second or third with different sorts of seed, before the proper season arrives for planting in the fields and grounds appointed for the great and general crop.'

67. The principles of agriculture may be reduced to a very small compass, viz. imitating the native habitations and propagating the species of the several plants. To improve their qualities, as also to increase their number, the chief thing requisite is, to facilitate their mode of nutrition, by removing all obstacles, by draining, and numerous other operations above and below

the soil; also by supplying food, as by manuring, &c. The manure best adapted is decayed plants of their own species; some containing peculiar substances in their composition, as wheat for instance, which contains gluten and phosphate of lime. It is also important to ameliorate the climate, by increasing or diminishing its temperature, according to the nature of the plant; to shelter and shade some species of vegetables by means of walls, hedges, banks, or sloping surfaces, to receive more directly or indirectly the solar rays, with numerous other iota, which a slight practice of agriculture will suggest; as thinning away the leaves immediately overshadowing fruits and flowers, blanching, shading, cuttings, seeds, &c.; imitating, by artificial applications of water, the dews and showers of heaven; cutting ridges for surface drainage, conduits, &c. To improve the quality, and increase the number of particular parts of vezetables, it is needful frequently to amputate all other parts that are unnecessary, as in pruning the vine; and to form new varieties, we must take advantage of their sexual difference, and imitate the example of animal nature in crossing the breed.

68. PRESERVATION OF FRUITS.-In the preservation of the fruits, when produced, considerable judgment is necessary. The great object is to prevent, as long as possible, the process of chemical de-composition. The air around de priving them of their carbon, the moisture within enfeebling the affinity of their component elements; and together with heat tending greatly to promote their de-composition; potatoes, turnips, &c. are best preserved by drying them in the sun, and burying them in a dry soil, a few degrees above the freezing point of temperature. By drying in the sun, and afterwards bring in dry cool pits, closed, so as to shut out the air, some may be effectually preserved for many years; the internal air becoming carbonic acid gas, in which no animal can live, and in which, without oxygen, no seed will vegetate.

69. Drying in ovens answers the same purpose as drying in the sun, and is one of the most obvious modes of preserving vegetables for use: it destroys, however, in most cases, the principle of life in seeds, as also in the roots and sections of the shoots of ligneous plants, and thus prevents the possibility of future germination. It is of capital importance in preservation, after the vegetables are thoroughly dried, so to bury them, as effectually to exclude the atmospheric air, by which means, not only decompo sition is prevented, but the ravages of insects, vermin, and even vegetation. It was no proof of the skill of our ancestors, when they changed this practice of the ancients, for the less successful mode of enclosing in granaries and storehouses. The Remans preserved their com in chambers hewn out of dry rock, a practice, the advantages of which, set forth by their most valuable writers, are justified by modern experience. The Moors, from time immemorial, have been accustomed to bury their corn in the sides of hills, by which famines have been frequently prevented, and supplies readily obtained after the

most deleterious seasons. The Chinese at the present time bury their store-grain in deep pits in dry soil, a practice which has distinguished them from the earliest history. The origin, of these expedients, are all obvious imitations of what commonly takes place in nature: they are applications of natural principles of which the whole circle of sciences, with all the numerous modifications and practises founded upon them, are but a varied development, and as such, may be satisfactorily explained by chemistry and physiology. The instinct of animals has guided men of genius in many cases to the discovery of them; as in the winter store of the hedge-hog, in the repository of the ant, whilst the successful preservation of vegetable substances on this inferior scale, has demonstrated their practical importance more effectually than a thousand arguments.

70. MINERALOGY.-Our next object in the present article, will be to exhibit the science of agriculture in its immediate connexion with the mineral kingdom, including all the primary elements concerned in vegetation. Earths are the production of rocks, exposed on the earth's surface; and soils are earths mixed with certain proportions of the de-composed matter, arising from the bodies of dead plants and animals. With respect to its geological structure, the under surface of the earth presents four distinct species of rocky substances. The first, consisting chiefly of granite and marble, are called primitive; and are supposed to be co-eval with the formation of the world. The second series, sometimes called transition rocks, appear to be of more recent formation; and are probably the result of some great catastrophe. Of these, clay-slate is the most remarkable, to which may be added, trap or whinstone, sandstone, &c. Secondary rocks, as sandstones, limestones, conglomerations of fragments of other rocks, &c. form a third series. They probably owe their formation to local revolutions, and are indicated by their soft fragile texture, superincumbent situation, and horizontal position. The fourth and last series consists of irregular strata, of alluvial or earthy depositions from water assuming the modification of immense beds of clays, sands, or marls. Earths are variously composed according to the rocks or strata from which their elementary particles have been derived. Those formed from slate-rocks commonly assume the modification of blue clays; those from sandstones are called siliceous throughout their several varieties. The additions made by the decay of animal and vegetable substances, have given rise to the appellation of soils, which differ from earths inasmuch as they contain a greater or less portion of animal or vegetable matter. They are also distinguished by their friable texture, dark colour, and by the presence of some vegetable fibre or carbonaceous matter. The depth of soil upon cultivated grounds is only a few inches below the surface,

unless in crevices where they have been carried by the rains.

71. SECT. II.-A GENERAL VIEW OF SOILS, AND THEIR CULTIVATION. Soils are divided into two grand classes, primitive and secondary; the former consisting chiefly of inorganic matter, the latter of both organic and inorganic in mixtures. These two classes may be subdivided into orders depending on the presence or absence of saline, metallic, and carbonic matter. These orders form certain genera, calculated from the prevailing metals, earths, salts, carbon, &c. The species, the next inferior to the genera, is founded on their various mixtures. Varieties dependent upon colour or texture form component divisions of the species and subvarieties of the varieties, according to the relative dryness, richness, brightness, moisture, &c. To determine the genera of soil, the first thing is to ascertain the prevailing earth or earths, as clay, sand, lime, &c. or the particular rocks from which the soil has been produced, as basalt, granite, &c. The earths that prevail supply the generic name of the soil, as the calcareous soil, clayey soil, &c., but when two prevail equally, the names of both must be conjoined, basalt and sand, clay and sand, &c. Precision in the application of the terms greatly facilitates a knowledge of the subject. No soil should be called sandy that does not contain seven-eighths of sand, and if effervesing with acids should be called calcareous sandy soil, in opposition to that which is siliceous. Clayey soil should denominate land containing not less than one-sixth of impalpable earthy matter, freely effervescing with acids. Peaty soil should contain one-half or more of vegetable matter. When the soil is composed of the decomposed matter from one particular rock, the name of that rock may be applied. On this principle fine red earth, found above decomposing basalt, may be called basaltic soil; that in which quartz, and mica are abundant, may be denominated granitic soil, &c. Alluvial soil, or those formed by the depositions of rivers, are commonly the most difficult to define, but may be for the most part designated by the terms siliceous, calcareous, argillaceous, &c., in some cases saline. The species of soil is determined by the mixture of matters rather than by the colour or texture, the latter being the characteristic distinctions of varieties. A clayey soil, with sand, is denominated a sandy, clayey species; if yellow, it might be called a yellow sandy clay, which would express the genus, species, and variety. A soil containing equal parts of clay, lime, and sand, would be called clay, lime, and sand entire; or to express at the same time its varieties, it might be called a brown, stiff, free, fine, or coarse entire clay, lime, and sand. The common genera, species, and varieties of soils, are enumerated in the following table.

73. DISCOVERING QUALITIES OF SOILS.e different qualities of soils and the conseent value to the cultivator, are discovered tanically by the natural plants produced upon m; chemically by analysis; and mechanically handling them.

74. The plants that grow upon the soil decide, the opinion of the farmer, its agricultural value th more popular certainty than even chemical alysis. The most valuable soils for the farmer stinguished by their several plants are the folwing: Argillaceous, distinguished by thalicim flavum, carex, many species; juncus, rious species; tussilago farfara, potentilla iserina, argentea, reptans, and others. The ssilago farfara is an universal symptom of an gillaceous soil. Calcareous soil produces galim pusillum, veronica spicata, lithospermum ficinale, purpuro-cæruleum, campanula glometa, and hybrida, cistus helianthemum, clematis ita alba, &c. Silicious soil bears the veronica riphyllus, and verna, arenaria rubra, &c. silena aglica, and other species. Ferruginous soil roduces the rumex acetosa, and acetosella. 'eaty soil bears vaccinium myrtillus, uliginoam and oxycoccus: erica four species, tormenlla officinalis. Saline soil produces the zostera arina, pulmonaria maritima, convolvulus solanella, arenaria maritima, &c. Aquatic soil >ears caltha palustris, hippuris vulgaris, lythrum alicaria, samolus valerandi, &c. Dry soils re distinguished by the rumex acetosella, trifoium arvense, acinos vulgaris, thymus serpyllum, irenaria rubra, &c. Some of these plants afford, t is to be confessed, an evidence not always to be depended upon; but the saintfoin is an evidence of a calcareous soil; coltsfoot (Tussilago farfara) of blue clay; arenaria rubra of poor sand; the small wood-sorrell of the presence of iron and peat; arundo phragmites (the common reed grass), polygonum amphibium (the common pond weed), grow in good alluvial soil; whilst the equisetum arvense (field horse tail), indicates a cold retentive subsoil. Anagallis arvensis, sherardia arvensis, lithospemium arvense, and fedia olitoria, i. e. field pimpernell, field madder, corn gromwell, and lambs lettuce, grow in cultivated black loamy soil, on a dry bottom. Soil of this description, when wet, produces the stachys palustris, or (clown's all heal). The presence of the red dead nettle (lamium purpureum) evinces a light sandy soil, as also the shepherd's purse, (thalspi bursa pastoris.) Where the parsley piert, (aphanes arvensis) is found, the soil is unproductive; where the corn spurry (spergula arvensis) grows thick, the ground has been too much harrowed. Where the common ragwort and the cornthistle (senecio jacobaa, and = serratula arvensis) grow freely, the soil generally is fertile consisting of light strong loams. It is, however, the whitlow grass, and the common knawell, (draba muralis, and scleranthus annuus) which indicate extremely poor, dry, and sandy soil. The common rest harrow, (ononis hircina) is often found on dry pasture, and where the soil is incumbent on rotten rock. Considerable dependence is to be placed on those plants which are common to aquatic, peaty, and saline soils, as indicating their several qualities.

75. QUALITY OF SOIL EVINCED BY CUEMICAL ANALYSIS.-The discovery of the qualities of soils by chemical analysis is extremely diffcult, and is seldom performed successfully by the cultivator. In selecting specimens, care should be taken to procure them from different situations. When the field is in one part calcareous, and in another silicious, the portions should be separately submitted to experiment. From two to four hundred grains is the proper quantity for a perfect analysis, which should be taken in fair weather, and when perfectly dry, preserved in phials, closed with ground glass stoppers, till the period of examination. The soil best for culture according to the analysis of Bergman, contains four parts of clay, three of sand, two of calcareous earth, and one of magnesia. Kirwan observes, that the fertility of the soil depends much upon its capacity for retaining water. The ingredients of the soil, however, do not always correspond to the nature of the climate; the quantity of rain that fertilizes a wet soil, cannot be equally suited to a dry one. Silica in the soil exists under the modification of sand, alumina under that of clay. Soils in which the sand preponderates, are called dry, retaining the least moisture: those in which clay preponderates, retaining the greatest portion, are called wet. Before either of them are capable of culture, the excess must be retrenched, or the defect supplied. Besides the above, the properties of soil may be ascertained mechanically. Its specific gravity may be ascertained by introducing into a phial known to contain a certain weight of water, equal volumes of water, and of soil; to do which, it is necessary to pour in the water first, till the vessel is half full, and then put in earth till it reaches the brim. The difference between the weight of the soil and water will be the result. Thus, if a bottle which holds 400 grains of water, gains 200 grains when half filled with water, and half with soil; the specific gravity of the soil is 2; that is, it will be twice as heavy as water. Clay in any soil may be known by its tenacity; sand by its roughness. Calcareous matter in soil is known by its effervescing freely upon meeting with an acid. The presence of organized matter in soil, may be ascertained by weighing it when it is perfectly dry; and after having subjected it to a red heat, weighing it again, which will give the proportion of organic matter. Metallic oxydes in soil may in general be known by their colour. Ferruginous soils are red and yellow; cupreous soils are interspersed with greenish streaks; salt, coals, sulphur, &c. may be known by the appearance of the water in such soils, and also by the peculiarity of vegetation.

76. USES OF SOIL.-Earths are of no further service to plants than providing them with a medium by which they fix themselves to the globe; and even the portions of earth taken up into them by vegetation, are not convertible to any other substance; and are supposed to afford the plant nothing but firmness of organization, as wheat, oats, and many hollow stalked grasses, have an epidermis of earth to defend them from the attacks of insects and parasitical plants. Plants are nourished exclusively by means of water and