perfection, and in the most beneficial proportions, it becomes deteriorated by use, so as to require constant attention. Such an arrangement is best fitted for the present condition of the human race. There is here something calculated to stimulate industry and ingenuity, by holding out the prospect of advantage. Nor must it be forgotten, that the various materials necessary for the amelioration of the soil, are very generally within reach; and that the operations by which these materials may be rendered available, are in themselves sufficiently simple, and require instruments by no means complicated. Were it otherwise, the condition would be unsuitable to the circumstances of man, except when considerably advanced in civilization; and obstacles would be interposed at the very outset, which might prove fatal to his improvement, not only in this but in other respects. Let us only suppose, for a moment, what would be the consequence to agricultural progress in its earlier stages, if the only method of improving the soil were by excavating manure, for example, from the hard rock, as is the case in the application of lime, and causing it to undergo decomposition by fire. Such an operation would obviously be too recondite to be discovered by man in an uncivilized state, and too difficult and complicated to be generally reduced to practice. But the ordinary means by which the soil is improved, are readily at hand, and are too obvious not to be discovered in the natural course of things, without scientific knowledge, or more skill than is acquired by man in a very early stage of society. As soon as he has begun to turn up the earth, he discovers that the vegetables with which its surface was covered fertilize the soil as they decay; the dung accidentally dropped, he observes to give peculiar vigour to the vegetation in those places where it has been covered in; the land he finds to be better adapted to the growth of plants, when cleaned of weeds and pulverized; too much and too little moisture he experiences to be equally injurious. It is thus that, in a short time, and with the simple exercise of a little acuteness of observation, the great and leading principles of agriculture are unfolded, and the soil yields its powers to man without the aid of science. The importance of all this facility will appear more clearly, when we consider how much of human improvement and happiness depends on the resources of agriculture. It is from this employment, indeed, that the advancement of society in the arts and sciences, may be considered as mainly taking its origin. While men gain their subsistence by hunting or fishing, they are always in a savage state, having seldom any fixed habitations, but roaming through the forests, or frequenting the sea-coasts or the banks of rivers, wherever their means of subsistence in the various seasons of the year may be found most abundant. The shepherd state, indeed, implies considerable advancement beyond that which we have mentioned. It supposes the recognition of personal property, and sometimes also, but by no means generally, a settlement in a particular locality, and the possession of a few domestic comforts. But it is not till man has advanced a step further, and has begun to cultivate the soil, that he makes any very important progress in civilization, or becomes bound permanently with his fellows in the bands of a well-organized community. It may, therefore, be regarded as a proof of wise and beneficent arrangement, not only that the soil requires and rewards cultivation, but also that the means by which that cultivation may be effected are so easy of access, and so patent to general observation. NINTH WEEK-TUESDAY. FORMATION OF SOILS. I HAVE already observed, that the simple earths are produced by the decomposition of rocks, and it may be proper to show how this process takes place. This I shall do in the words of Sir Humphrey Davy, who has expressed himself with much philosophical precision, and, notwithstanding the scientific terms he employs, with sufficient plainness to make his general meaning understood by an unscientific reader. "The manner in which rocks are converted into soils, may be easily conceived, by referring to the instance of soft granite. This substance consists of three ingredients, quartz, feldspar, and mica. The quartz is almost pure silicious earth, in a crystalline form. The feldspar and mica are very compounded substances, but contain silica, alumina, and oxide of iron. In the feldspar there is usually lime and potassa; in the mica, lime and magnesia. When a granitic rock of this kind has been long exposed to the influence of air and water, the lime and the potassa contained in its constituent parts, are acted upon by water or carbonic acid, and the oxide of iron, which is almost always in its least oxidized state, tends to combine with more oxygen. The consequence is, that the feldspar decomposes, and likewise the mica, but the first the most rapidly. The feldspar, which is, as it were, the cement of the stone, forms a fine clay; the mica, partially decomposed, mixes with it as sand; and the undecomposed quartz appears as gravel, or sand of different degrees of fineness. As soon as the smallest layer of earth is formed on the surface of a rock, the seeds of lichens, mosses, and other imperfect vegetables, which are constantly floating in the atmosphere, and which have made it their resting-place, begin to vegetate. Their death, decomposition, and decay, afford a certain quantity of organizable matter, which mixes with the earthy materials of the rock; in this improved soil, more perfect plants are capable of subsisting. These, in their turn, absorb nourishment from water and the atmosphere, and, after perishing, afford new materials to those already provided. The decomposition of the rock still continues; and at length, by slow and gradual pro cesses, a soil is formed, in which even forest trees can fix their roots, and which is fitted to reward the labours of the cultivator."* If The processes here described are such as are at this moment proceeding on the surface of the earth. But they do not of themselves account for the phenomena which the surface of the earth at present displays. the reader has at all attended to what has been said in the Winter volume, respecting geological changes and revolutions, he will understand in what manner these operations may have been accelerated, and the various soils, thus formed, may have been removed and mixed. The hand of the great Creator is as conspicuous in the one class of operations as in the other; and while we trace these operations, we should never lose sight of Him, who not only at first endowed matter with such tendencies, but who afterward presided over and controlled all its convulsions, so as to fulfil his high behests, and finally, to produce a world so admirably fitted for the habitation of a race of rational beings, such as man. Peaty soils are produced by very different causes from those already mentioned. They arise from the accumulation of neglected vegetable matter in moist situations. Where successive generations of vegetables have grown upon a soil, Sir H. Davy observes, unless part of their produce has been carried off by man, or consumed by animals, the vegetable matter increases in such a proportion, that the soil approaches to a peat in its nature; and, if in a situation where it can receive water from a higher district, it becomes spongy and permeated by that fluid, and is generally rendered incapable of supporting the nobler class of vegetables. Another mode in which peat has been formed, is by the gradual accumulation and decomposition of aquatic plants in shallow lakes and stagnant pools. This kind of peat is of a more loose and spongy quality, and the fermentation which takes place * Elements of Agricultural Chemistry, p. 188. man. seems to be of a different kind, more gaseous matter being evolved. What has greatly contributed to the growth of peat, is the destruction of ancient forests, either by the operation of some natural cause, or by the hand of In Britain, and various parts of the European continent, the conquests of the Romans seem greatly to have contributed to this. That adventurous and warlike people, found it necessary, for the evolutions of their armies, to destroy the extensive woods which formed the natural fastnesses of the inhabitants; and, having accomplished this object by fire or by other means, they suffered the unconsumed trees to lie where they fell ; and these, where the ground was level, damming up the little brooks and rills, and causing the moisture to accumulate, gave rise to a coarse vegetation, which, in process of time, formed into extensive morasses. The existence of great quantities of wood, in various stages of decomposition, having sometimes very obviously undergone the action of fire, sometimes of the hatchet, in almost all the mosses of this country, may readily be accounted for on this supposition. It is instructive to observe, in the management of soils, a principle not yet adverted to, but brought into view by this account of the origin of peat-bogs and mosses. Land, as appears by this example, is capable of deterioration by neglect or abuse, as well as of improvement by cultivation. The peaty soil of Great Britain and Ireland, and, indeed, it has been alleged, of the habitable globe, constitutes nearly one-fourth of the whole surface. This ungenial soil is constantly on the increase, wherever it is not arrested in its progress by human industry. Here, then, we have a stimulus to exertion, the very converse of that previously mentioned. The former holds out a reward to industry, the latter acts as a punishment upon negligence and sloth. This is entirely in conformity with the operations of Providence in other respects, and, indeed, in various modes, enters into all the operations of agriculture. While judicious manage |