The conservatory has been already treated of, as an appendage to the mansion, in pp. 54. to 57. inclusive, and several designs for conservatories and other kinds of plant-houses will be given in an after part of this work. To be truly enjoyed as a luxury, it ought to be connected with the house, and entered from one or more of the principal living rooms. The flower-garden ought to be near the conservatory, in order that it may be at all times reached from the house in a few minutes, and also that it may, by its richness and high keeping, add to the appearance of art and refinement in the immediate vicinity of the mansion. Conservatories may either be of glass on all sides, and connected with the mansion by one end; or they may be placed lengthwise against the mansion, or against a wall projected from it, or against the offices; in either of which cases, only the front and the roof need to be of glass. The latter kind of conservatories, or green-houses, are always heated and managed at less expense in the winter season, than those which are of glass on all sides; and the plants in all conservatories always look well in an inverse proportion to the artificial heat required.

The main reason why a conservatory with glass only on one side requires so much less artificial heat in the winter time is, that the glased side is generally contrived so as to front the south; and, while this and the glass roof admit all the rays that the sun gives at that season, the thick wall on the north side protects the conservatory from the cold north winds. A very convenient arrangement, where the aspect is suitable, is, to place the conservatory against the exterior wall of the buildings of the kitchen-court; and, between this and the kitchen-garden, to form a flued conservative wall against the drying-ground, poultry-yard, and stables, and to continue it on, either in straight or in curved lines, or in a combination of these, as far as the wall of the kitchen-garden. The flower-garden might, in this case, be placed in some part of the lawn in front of the conservative wall, that is to say, the general flower-garden; because, where there is a great attachment to plants, and the place consists of two or three acres, there may be an American garden, an ericetum, an alpine garden, a marsh garden, an aquarium, etc (which may all be considered as belonging to the class of flower-gardens), in various parts of the grounds.

248. The drainage of the house and offices, and of the entire place, may next be taken into consideration. In the country, in general, there are no public sewers, as there are near large towns; but, nevertheless, there are roadside, or field, ditches, and natural brooks, which receive the surface water produced by the rains on the given tract of country; and into these all drains, whether for drying the soil, or carrying off the waste water from the dwelling-house and offices, must be made to empty themselves. In general, there ought to be one main drain from the house, through the centre of the courts of offices, to a large liquid manure tank; or, what is preferable, there may be two tanks, that the one may be filling while the other is being emptied. If the manure produced in these tanks be properly valued, and, consequently, carried away as it is duly fermented, there will seldom be any overflow; but nevertheless, to provide against the possibility of this occurring, there ought to be a drain from the tanks continued to the boundary of the property, and thence into the nearest ditch or brook.

This drain, between its origin at the house and the manure tanks, ought to have all the communications with it furnished with proper traps, to prevent the rising of smells; and, where it communicates with the tanks, and also at its commencement and at its exit into the public drain, there ought to be either cast-iron gratings, or water traps, to exclude rats.

249. Traps to prevent smells are made of cast iron, and they are generally from 6 in. to 1 ft. square on the upper surface, according to the quantity of water that is supposed likely to pass through them. The construction and action of such a trap will readily be understood by the section,fig. 73.; in which x is the grated covering to the basin of the trap, and y the funnel through which the water escapes to the drain. Water falling into this trap through the cover (x) escapes by the funnel (y); but the bell-shaped cover placed over this funnel, by dipping into the water all round it, prevents the escape of air upwards. In order that such a trap may be protected from the effects of frost, it is convenient to have it sunk 1 ft. or 1 ft. 6 in. in the ground, and covered with an ordinary cast-iron grating, on a level with the surrounding surface. The funnel may communicate with the drain, either through the top or sides. As the basin of the trap will be liable, after being a certain time in use, to become filled up with sand or other earthy matters, the grated cover to which the bell is attached is not fixed to the basin, but may be lifted out at pleasure, to admit of emptying the latter.

250. A water-trap, for the purpose of preventing the progress of rats along a drain, is formed by sinking a pit in the bottom of the drain, say 1 ft 6 in. or 2 ft. deep, and suspending a piece of flagstone across it, from within half an inch of the cover of the drain, to within 6 in. of its bottom; the flagstone being built into the sides of the drain and pit. This construction will readily be understood by the vertical section, fig. 74., and the horizontal section, fig. 75. In these sections, a a represent the line of direction of the drain; b the flagstone which forms the dip or trap; and e the flagstone which serves as a cover, and which admits of being taken off without disturbing the dip-stone, in order to clear out the well, or pit, of the trap. The action of such a trap is sufficiently obvious. No animal can pass it without diving under the dip-stone; and this, it is ascertained from experience, rats will not do, unless where the water is clear, and both sides of the trap are fully exposed to the day, in which case they will dive under the dip-stone and ascend on the other side, though the stone should descend several feet into the pit.

It should be observed, that only a small space of about half an inch is left between the dip-stone and the cover; this space is essential, in order to admit the passage of air; for though the water would escape without it, yet it would be at a much lower rate. It may be useful to observe here, that all underground drains from offices, or from any part of an estate, which are intended to carry away night soil, or any earthy matter, ought to have a certain slope or inclination; with the bottom of the drain not flat, but concave, and generally so much so as to form the section of a semicircle. A semicircular bottom, and a slope of 11/2 in. in 10 ft., it has been ascertained by builders, will enable any drain, with a tolerable supply of water, to carry off all the nightsoil suspended in it; but, where there are sand or small gravel, pieces of bones, broken crockery, and other matters of that description, to be carried away, the slope requires to be at least 3 in. in 10 ft.

251. If the subsoil of the property be dry, very few drains in the grounds, for the purpose of drying the soil, will be required; but, if the soil be loamy, or on a retentive bottom, every part of it will require under-draining. The kitchen-garden must be more thoroughly drained than the general surface, which is to be laid down under grass, or planted with trees, because the excellence of culinary produce depends chiefly on the culture of the soil; and an extra attention to drainage must be paid in the flower-garden, and in all those parts of the lawn (especially such as are near the gravel-walks) which are liable to be much walked on in autumn or spring. Whether the subsoil be naturally dry or wet, every walk and road, whether in the kitchen-garden, the flower-garden, the pleasure-ground, or forming the approach roads to the mansion, and the branches to the offices, will require to be drained, for the sake of absorbing as completely as possible the water that falls on them during heavy rains, or is produced by the thawing of snow.

For this purpose, a drain should be conducted along one side of the walk, under the gravel in the kitchen-garden, and either under the gravel, or under the turf, in the pleasure-grounds; and to this drain small grated openings should be made, at regular distances, along one side of the walk. Where the walks in the pleasure-ground are of great length, branch drains require to be introduced at certain distances in the lowest situations, in order to conduct the water collected in the drains along the walks to the nearest public drain. The drains along the walks should be what are called box or barrel drains; the former having a bottom and square sides, with a flagstone cover, as in fig. 76.; and the latter being a circular cylinder of brickwork, a section of which is shown in fig. 77. Small iron or stone gratings on the surface communicate with the drains by short upright shafts, 9 in. square in the clear within; and, in the bottom of the drain, immediately under each shaft, a pit is formed, and walled on the sides, a foot square within, and from 1 ft to 2 ft. or more in depth, as in the section fig, 78. The use of this pit is to receive the sand that is carried through the grating with the water, immediately after very heavy showers in rammer; and thus to prevent the sand from being carried along the drain, and in a few years choking it up.

Once a year, the grating at top is taken off, and the deposit of sand taken out with a spade having a kneed blade;, and by this means not only may the drains be kept quite clear and effective for many years, but much smaller and less expensive drains may be made at first. Where the subsoil is sandy, gravelly, or rocky, and where it is not considered essential to use the walks immediately after rain, drains of the box or barrel kind may be dispensed with, and common nibble drains formed by filling up a trench with round stones, to within a few inches of the surface, as in fig. 79., and terminating it by a somewhat coarser portion of the common gravel used in forming the walk, through which the water will percolate, throughout the whole length of the drain. In flower-gardens, and indeed in extensive shrubberies, brick traps of the kind described above may be dispensed with, and the bell-trap represented in fig. 73., or some other trap of the kind, may be made -use of; but, in this case, these traps must be cleaned out after every shower of rain.