In the-greenhouses the most perfect ventilation is provided for by opening all the side lights, so that during the hottest weather the houses may be kept comparatively cool; and, after the occurrence of great moisture, they may likewise immediately be dried. Beneath the stages, moreover, there are small slides or shutters, for further ventilation; and these are very useful in winter, as the air they will admit passes over the heating pipes. By their means, likewise, the floor and lower parts of the house can be kept dry. The stages are, for the most part, covered with a thin coating of gravel; and, to bring the plants as near as possible to the glass, and secure to them a greater amount of air, and guard them against becoming too moist, each of the specimens is generally raised on a large pot, so as to stand from 18 to 30 inches above the stage.

It will of course be impossible, were it even worth attempting, to do more than point out some of the general features of this collection. The two principal greenhouses contain nothing but specimens. The plants in them that are most conspicuous are Boronias, Epacrises, Polygalis, Eriostemons, Pimeleas, Leschenaultias, Croweas, Chironias, Choro-zemas, Hoveas, etc, with a few climbing plants trained to low trellises. Crowea saligna, Coronia crenata and serrulata, Chorozema cordata, Pimelea spectabilis, all the Eriostemons, especially E. buxifolium and intermedium, and the charming old Leschenaultia formosa, are some of the plants here cultivated, which flower abundantly in all stages of their growth, and are of a free and excellent habit. Some idea of the size of many of the plants will be conveyed by mentioning that Pimelea spectabilis is 27 feet in circumference, and that, from the edge of the pot over the whole surface of the plant, there is scarcely space enough to allow of the hand being introduced between any of the branches. Nearly every one of the shoots is crowned with a bunch of blossoms in the summer.

Gompholo-biumpolymorphum grandiflorumis treated as a bush ,and makes a beautiful plant in this state.

In the stove the plants are equally good of their kind. A great many handsome climbers are here grown to trellises, and a few of this tribe are also trained up the slender pillars which support the roof. The Alamanda cathartica, Schotti, and grandiflora, Stepkanotis floribunda, Convolvulus pentanthus, Hoya imperialis and Bedvrilli, several species of Ipomaea, Echites, aeschynanthus, and Combretum, Clerodendron splendens, etc, are some of the principal dwarf climbers, and are in great perfection. Medinilla $pecio8a, a rare and exceedingly ornamental species, with very large leaves and conspicuous drooping spikes of pink flowers succeeded by showy crimson fruit, is in an excellent state, and blooms for several months.

A glass partition, with a light iron frame (the rest of the houses being of wood,) separates the commoner stove from the orchid houses, and from the compartment devoted to the Amherstia. Of this last, there is an extraordinary specimen, which is, perhaps, the greatest feature of the whole collection. It is now quite a little tree, although it has only been here four or five years, and has flowered here for the first time in Europe, very few other plants of it existing in England. At the present time (January, 1851) it is again

As it deserves, the plant here receives every attention. It is placed near the back of the house, and grows in a large tub, plunged in a bed of bark. An extra heating pipe passes round the plant, within about two yards of the tub, and an open zinc gutter for containing water is fixed to the top of this pipe. In the front of the plant is a small basin for aquatic plants; and provision is made for Spreading over the plant, beneath the glass, an oiled calico screen, which runs on rollers, and which, when used, at once furnishes any required shade, and protects the leaves of the plant from the water that might drop from the roof. A high temperature and a most atmosphere are preserved.

Besides some interesting aquatics, a number of gold fish are kept in the basin opposite the Amherstia, which is, moreover, furnished with a fountain. The back wall of this house is also partly clothed with ferns and orchids, and a few of the more purely tropical stove plants and orchids are placed at the sides of the house; but a considerable open space is wisely preserved in the middle, so as to give more consequence to the Amherstia, and cause it to be better seen. The Barrtngtonia, with its noble leaves, seems quite at home in this close stove; and there is a large plant of the curious Grammatophyllum, with a very beautiful climbing Lycopodium, which has large bluish fronds.

One of two small orchid houses on either side of that which contains the Amherstia, is used for Mexican species, and the other for such as require a rather higher temperature. The collection of both these tribes is good, and the plants well grown, but not remarkable. By the side of the paved path, and partly under the stage, there is an open channel or gutter provided for carrying off any water that may be used in syringing the plants or washing the paths.

Behind the larger group of houses there is a very nice heath house, with a western aspect, and full of the choicest specimens in admirable health. Other and smaller houses are devoted to Pelargoniums, which are placed on stages, to Azaleas, to stove plants requiring bottom heat, and to miscellaneous articles. The Axaleas stand in pots, like the green-house specimens, and are most splendid examples of cultivation. As with the green-house plants, (and also with the heaths,) there are successional or younger specimens, which are preparing to supply the place of the larger ones when these wear out or become shabby.

A small stove, which contains a bark bed, in addition to the usual heating power, is almost wholly filled with Ixoras of different kinds, plunged in the bark. They are superb plants, and this method of treatment keeps them very luxuriant. I, javanica, which is nearly new, has attained a considerable size here, and produces its pale orange flowers most profusely. An extraordinary specimen of Gardenia Fortuni, some Rondeletias, etc, are kept in this house likewise; and a wire trellis is beautifully covered with the charming Dipladenia crassinoda. Another small stove, with a similar bark bed in the center, and heated by a tank traversed with hot-water pipes beneath the bark bed, is occupied with various kinds of aeschynanthus, Gardenias, and such other plants as flourish best with bottom heat. The very best effects result from this mode of plunging certain kinds of stove plants in a material supplying bottom heat, as they never thrive half so well under any other system of management.

A span-roofed house has lately been built for the East Indian orchids, on the north side of the area containing the plant-houses. It is heated by hot-water pipes, which pass all round it in the ordinary way, and has no other heating material. The species belonging to the Vanda tribe are chiefly grown here. There are some noble plants of derides and Argracum eburneum. And the entire contents of the house are so excellent that bring this class of orchids together in one house, as well because they can thus be more appropriately treated, as on account of the effect produced by such a combination of exclusively elegant forms.

Calceolarias, Cinerarias, tall Cacti, and many tribes that we need not mention, are cultivated here in the best order in other houses and pits. Our notice, indeed, can by no means do justice to the place, which contains, even among its minor features and mechanical agents, very much that must interest the general cultivator. For example, there are several large box-like frames, made high enough to contain moderately large specimen plants, and capable of being covered with oiled calico or with glass lights, and ventilated by small slides at the ends, which, with an eastern aspect, are well adapted for receiving plants that have been newly potted, or such as are out of health, or those which may be wanted to be kept from blooming so soon, or to be preserved longer in flower. There are also some very convenient span-roofed pits, the lights of which work on a kind of hooklike hinge at the top, and are fastened down by iron pins in windy weather. There can be little doubt that pits of this description, made about 7 ft. wide and 4 ft. high (or a little higher) in the center, with the lights to lift up (not slide) from the side, and capable of being taken off altogether if required, are in all respects the cheapest and the most convenient, and the best structures in which to grow those green-house plants that may be wanted for decorating a conservatory, drawing-room, or other place where flowers are chiefly demanded.

As a screen to some of the out-buildings in the plant house department, a strong privet hedge is employed, the treatment of which struck us as worth mentioning. The top of it is cut into a series of crescent shapes, the hollow of each crescent having the closely-pruned head of a standard rose just rising above it. A character by no means commonplace, and which may serve as a hint to improve upon, is thus obtained.

The period at which the greatest display of flowers may be seen at this place, is during the month of May, when the majority of the house plants are in their highest glory. In June, also, they are almost equally fine; and in so large an establishment there will, of course, be many plants in flower at all seasons.