[rater is not to be forgotten. If a streamlet can be brought to flow through the garden, it may be rendered conducive both to convenience and amenity : where this cannot be accomplished, the situation should be such that water may he conveyed by pipes from some neighbouring stream ; soft or river water being greatly preferable, for the purposes of the horticulturist, to that of springs or wells. 'Where running water cannot be commanded, re course is had to a lake or pond, it being known that water freely exposed to the air and sunshine for some time, be comes comparatively soft, and fit for the nourishment of' plants.
In selecting ground for a garden, the plants growing na turally on the surface should be noted, as from these a pret ty correct opinion may be formed of the qualities of the soil. The subsoil should also be examined. If this be radically bad, such as an iron-till mixed with gravel, no draining, trenching, or manuring, will ever prove an effectual reme dy ; if, on the contrary, the subsoil be tolerably good, the surface may be greatly meliorated by these means. In every garden, two varieties of soil are wanted, a strong and a light one, or, in other words, a clayey loam and a sandy loam, different plants requiring these respective kinds. For the general soil, a loam of middling quality, but par takiLg rather of the sandy than the clayey, is accounted the best.
Enclosure Walls.
40. When the situation is fixed on, the next considera tion is the enclosing with walls. Supposing a garden to be about an acre in extent, and the ground sloping gently to the south, the rule is, that the north wall may be 14 feet high ; the south wall, 10 ; and the other walls, about 12. In a larger garden, containing perhaps four acres, the north wall is sometimes raised 18 feet high ; the side walls, or those on the east and west, 15 ; and the south wall, not more than 12. On a dead level the north wall is generally made 16 feet high ; the cast and west walls I31; and the south wall 11. It may be observed, that walls higher than 12, or at most 14 feet, are necessary only for pear-trees; peach, nectarines, apricot and plum-trees seldom requiring more than 12 feet. It may also be right to notice, that the terms north and south wall, are here used to denote the north and south sides of a square or parallelogram ; but that, in speaking of wall fruit, if it be said that peach or fig trees require a south wall, this must be understood to mean a wall with a south aspect, or what is in reality the north wall of the garden. There are two motives therefore for raising this wall some feet higher than the others ; first, sheltering the garden from the northern blast ; and, in the next place, the procuring of ample space for training the finer kinds of fruit-trees on the south side of the wall, or best aspect of the garden. Under the denomination of finer kinds of fruit-trees are to be understood not only peaches, nectarines, apricots and plums, but some of the French pears, such as the chaumontel, colmart, and crassanc. Ma
ny gardeners are of opinion, that the best aspect for a fruit wall in this country is about one point to the eastward of south ; such walls enjoying the benefit of the morning sun, and being turned a little from the violent west and south west winds. South-east is, for the same reasons, account ed by many, a better aspect than south-west. The south west and west walls are assigned to fruits which do not re quire so much heat to ripen them as is necessary to those above mentioned ; such arc cherries, many kinds of pears, and apples. The north walls are appropriated to apples and pears for baking, plums and morella cherries for pre serving ; and a few may-duke cherry, white currant and gooseberry trees, are trained against these walls, with the view of their affording a late crop.
Bricks, it is generally allowed, are the best material of which to construct the walls. The foundation and base ment are often made of common building sandstone, while the superstructure is brick ; and sometimes the back part of the wall is of sandstone, and the front only of brick. Sandstone which rises in flags is the best substitute for bricks. Both kinds of materials admit of the branches of the trees being nailed in regularly, and without difficulty. Where the walls are of common rubble building, a trellis of spars is sometimes placed against them, and to this trel lis the branches are tied with osier-twigs or rope-yarn. This is regarded as a very good plan ; but the expellee is considerable, as, to prevent the lodging of insects, the trel lis must be smooth and painted. The trees thus enjoy the shelter and reflected heat of the wall, without being injured by its dampness in rainy weather ; and as the wall is not in jured by the driving and drawing of nails, there are fewer lurking-places for the wood-louse and the snail. The rails of the trellis are made closer or wider, according to the na ture of the tree to be trained against it. In a few instances in Scotland, walls have been built of different kinds of whinstone, chiefly greenstone and basalt. These minerals, on account of their almost black colour, are calculated to absorb and retain more heat than stones of a light hue : but it be considered, that it is not the heat retained by the wall which benefits the tree, so much as the heat reflected from the wall. The proposal of painting walls black is, on the same principle, not admissible. It may here be of some importance to remark, particularly as applicable to Scot land, that in building brick walls, bricklayers only should be employed ; stone-masons working as awkwardly and clumsily with bricks, as bricklayers would do with masses of whinstone.