532. In the course of this treatise, the different sizes of flower-pots have more than once been mentioned in the technical style employed by gardeners, such as " eights," " sixteens," &c., or " No. 1,"" No. 3," &c. These terms it may be proper here to explain. The meaning of them will be rendered obvious by a tabular view ; but it may first be observed, that potters usually make seven sizes, also called numbers, of pots ; that the pots of each par ticular size are sold in what are called casts ; and that the number of pots in a cast increases proportionally as the size of the pots decreases. Of No. 1., which is the largest kind of pot in common usc, there are eight in the cast, and a pot of this class is called either a No. 1," or an " eight." Pots larger than eights, or of extra size, such as 4 in the cast, are often made, for the accommodation of large plants ; 4ncl, on the other hand, pots of a smaller size than sixties are sometimes manufactured, particularly for holding small seedling plants, or very young Cape heaths. These very small pots are among gardeners call ed thumbs.
533. Plants suited to the green-house are extremely numerous, and constantly on the increase: the selection of them must depend on the taste of the owner, and the size of the house. To give any enumeration seems unne cessary : it may be sufficient to refer to those excellent lists, the Epitome of Hortus Kewensis, and the Cam bridge Catalogue; in these the plants suited to the green house are marked G; and their duration or character are indicated by the marks usually employed by botanists and gardeners; 0 for annual ; t for biennial; 2,( for peren nial; and 12 signifying that the plant is shrubby or arbo reous. In the first mentioned catalogue, the plants which require a black heath mould, or peat soil, have an aste risk * prefixed to them. In the Botanical Magazine, edited by Sims, (formerly mentioned § 18.), all new and curious green-house plants are figured and described as they come into notice.
534. To keep up the show of plants actually in flower in the green-house, especially in the early spring months, a usual and very proper expedient is, to plant a number of the common ornamental bulbous plants, in pots, in the month of October ; to forward these in the stove, and to place them, as the flowers appear, upon the shelves of the green-house. For this purpose sonic of the many varie ties of hyacinth, with single and double jonquil, white and yellow polyanthus-narcissus, Persian iris, and the early sweet-scented tulips, are well adapted. The jonquil bulbs, it may be observed, must be two years in the pots before they can be expected to flower properly.
535. We may take this opportunity of noticing the mode of bringing these bulbous plants into flower by means of water alone. It was described by 'Miller in a communica tion published in the 37t11 vol. of the Philosophical Trans actions, for 1731. November is the usual season ginning this sort of chamber-forcing. The flower-glasses are filled up to the bottom of the bulb with fresh soft wa ter ; and it is kept up to this point by adding to it as often as necessary. The water should be entirely changed once in the week or ten days. The glasses should be situated in a light room, where a fire is kept, and, if possible, near to windows exposed to the forenoon sun. If they be placed in a hot-house for a few weeks, they are greatly forward ed, and appear in perfect flower in January. The nu
merous varieties of 'hyacinths, raised by the incredible in dustry of the Dutch florists, answer extremely well for this purpose; likewise the different sorts, white and yel low, of the polyanthus-narcissus. The jonquil, also, is pretty well adapted ; but to many its fragrance is too powerful in a room. The small tulips, called Due de Vanthol, Claremont, and Pottebakker, may be treated in this way ; and the Persian iris is sometimes brought to flower, but is rather apt to fail. The common poetic nar cissus, and the common daffodil, may be made to bloom in the same way.
Conservatory.
536. The Conservatory is distinguished by its interior being laid out in beds and borders, in which exotic trees, shrubs and perennial plants are cultivated as in the natural soil. The sides and roof are of glass; and not unfrequently this last is so formed, that it can be removed during the summer months. The parapet wall should be arched, in order to allow the roots of plants in the border next to it to penetrate to the exterior border, in quest of food. In general the flue passes under the walk, and has cavities at each side, to let heated air escape through holes in the earthen tiles with which it is covered. The side borders are occupied with some of the smaller ornamental shrubs of New Holland, and with some others, which, though oc casionally placed in the open border, are apt to perish during winter ; such as the scarlet Fuchsia of Chili, and the fragrant Vervain of the same country (Verbena tri phylla); the Dutch double-flowered myrtle, and the tea plants. To these may be added some of the showy species of Polygala, Hermannia, and Gnidia. The bed in the middle of the house should be formed of compost soil to the depth of at least two feet ; the bottom being laid with some hard material, to prevent the roots Irom penetrating, particularly if the subsoil be indifferent. For the general soil, Nicol recommends a perfectly homogeneous compost of brown loam, being the sward of an old pasture, and 1.4th vegetable earth, preferring that resulting from decayed tree-leaves. The earth should not be screened ; indeed it is the better for having small stones mixed • with it. This middle bed is occupied by some lofty New Hol land plants, such as different species of Acacia, particu larly A. decurrens and longifolia ; the dwarfish fan-palm, Channerops humilis ; Clethra arborea, one of the orna ments of Madeira; Olive-trees, and frequently one or two of the Citrus genus. The different varieties, red and white, single and double, of the Japan rose (Camellia Japonica) deserve a place ; with Daphne odora ; the red flowered Anise-seed tree, Illicium Floridanum ; the Mala bar nut, (Justicia Adhatoda); the Camphor-tree (Laurus camphora); several of the elegant genus Protea, and one or two of the no less pleasing and curious genus Banksia. Where the house is of an oval or oblong square shape, and is composed of glass only on three sides, the back is covered with a trellis, to which several of the arborescent Cranes-bills, (such as Pelargonium inquinans, different varieties, P. peltatum, cuculatum, and laterifies) are train ed ; and these, when in flower, have a very brilliant ap pearance. In some conservatories,a small aquarium is form ed, where several of the foreign species of Nymplima and Menyanthes may be brought to flower.