Sandy soils next come under consideration. Soils of this description are managed with infinitely less trouble and at an expense greatly inferior to what clays re luire ; but at the same time, the crops produced from them are generally of smaller value. There are many varieties of sand, however, as well as of clay ; and in sonic parts of the island, the surface is little better utak* a bare barren sand, wile] ein artificial plants will not take root, unless a dose of clay or good earth is pre vious,y administered. This is not the soil meant by the farmer when he speaks of sands. To speak practically, the soil meant is one where sand is predominant, although there be several other earths in the mixture. From containing a great quantity ol sand, these soils are all loose and crumbling, aid never get into a clod, even in the driest weather. This is the great article of distinction beta ixt sands and sandy loan's. A sandy loam, owing to the clay that is in it, does not crumble down, or become loose like a real sand, but retains a degree of adhesion after wetness or drought, notwith standing the quantity or sand that is mixed with it. Perhaps a true sandy loam, incumbent upon a sound subsoil, is the most valuable of all soils. Upon such, every kind ol grain may be raised with advantage, and no soil is better calculated for turnips and grass.
The real sands are not favourable to the growth of wheat, unless when preceded by clover, which binds the surface, and confers a temporary strength for sus taining that grain. Aluch of the county of Norfolk is of this description ; and it is well known that few dis tricts of the kingdom yield a greater quantity of pro duce. Till Norfolk, however, was invigorated by clay and marl, nearly one half of it was little better than waste ; but by the success which accompanied the use of these auxiliaries, a new soil was in a manner created ; which, by a continuation of judicious management, has given a degree of fame to the husbandry of that county, far surpassing that of other districts naturally more fer tile.
We have now to speak of gravelly soils. The open porous nature of these soils disposes them to imbibe moisture, and to part with it with great facility ; from the latter of which circumstances they are subject to burn, as it is termed in dry seasons. The main differ ence between gravel and sand is, that the former is chiefly composed of small soft stones ; though, in some instances, the stones are of the silicious or flinty nature, and, in others, of the calcareous and chalky. From these constitutional circumstances arises the propriety of deepening gravelly soils by coats of marl or earth, and of keeping them fresh by frequent returns of grass, and repeated applications of manure. Gravelly soils, from the lightness of their texture, are not expensive or difficult in the means of cultivation. All the necessary business required for gravels may be carried forward with ease and expedition ; and such soils are, in general, soon brought into a proper state for the reception of crops.
From what is said respecting gravels, it will appear, that naturally they are barren, unless when mixed with other earths ; and that the surface of most of them exhibit the same appearance as the subsoil, or what is beyond the reach of the plough, were it not changed and meliorated by vegetable matters. The
constitutional qualities of gravels also point out the pro priety of ploughing them deep, so that the surface soil may be augmented and greater room given to the growth of the plants cultivated on them. A shallow ploughed gravel can stand no excess of weather, how ever enriched by manure. It is burnt up by a day or two of drought, and it is almost equally injured by an excessive fall of rain, unless the pan or firm bottom, which such soils easily gain, be frequently broken through by deep ploughing. According to an old adage, the top of clay, and bottom of gravel, arc best ; but though we cannot subscribe to the first part of the adage, being satisfied that deep ploughing is highly beneficial, except where the subsoil is of a poisonous nature, we arc certain that the latter is well founded, and ought never to be overlooked.
Peat earth, or moss, is the next kind of soil which we have to treat of ; though we are very uncertain whether, like loam and garden mould, it ought not to be viewed as an artificial soil, made and produced by certain sub stances deposited on the surface of the earth, and not one originally created, or to be found in the early ages. On these points philosophers are much at variance ; and the discordant opinions entertained by them, induce us to think, that very little real knowledge of the nature and properties of moss has hitherto been acquired. By one we arc told, that peat is a primitive earth, of antediluvian origin ; by another, that it is a vegetable, which grows and increases, and may continue to increase, till it swal lows up and destroys all other soils : by another, that it consists of ligneous and aquatic plants, brought into ac tion by the destruction of extensive forests, which abounded in Europe in former times ; these forests having been either destroyed by the Romans, or by tem pests, or having fallen into decay from natural causes. We are much inclined to adopt this last hypothesis, as it seems supported by the appearance which peat moss presents ; by facts which may be gathered from the his tory of Britain ; and, in particular, by the state and con dition of the very places where peat moss is now the pre dominant soil. It is truly wonderful, that so little is known on a subject of so much importance, not only to the prosperity of Britain, but even to that of the world. Noss covers, perhaps, one fourth of the habitable globe ; and surely few subjects better deserve consideration, than its removal, or improvement. We have lately re ceived much information concerning the origin of moss, from sonic essays published by the -everend Mr Rennie at Kilsyth ; and we indulge a hope, that when these es says are finished, the public will have in their possession more satisfactory accounts concerning the formation of moss, and the uses, to which it may be applied, than have hitherto been offered by the several writers who have attempted to investigate the origin of moss, and to illustrate the means of removing it.