This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
A further use to which these might be put, in the case of a tropical conservatory, might be to use each alternate column for taking away the rain water, and to make the others the means of heating the atmosphere, the hot water ascending up the center of the column, and descending down the sides. The heat, by this means, would be radiated to all parts of the house. The conducting pipes, both for the flow of the hot water and its return toward the boiler, should be placed under the walks, in a detached chamber, and, from these pipes, branch ones might be carried under the beds to afford bottom heat when required. These could easily be regulated by proper stopcocks placed on the mains, and could be reached by having ornamental brass ventilators fixed in the floor, and made to open sufficiently to admit a turncock key for the purpose of turning off or on the circulation to the beds under the plants. The branch pipes should be laid among the drainage, and not in the soil of the border. Such beds might also be very efficiently heated by forming brick-and-cement tanks under them, and supplying them either by branch nozzles from the mains that supply the columns, or by a separate set of main pipes, which would be better, as the pressure of the water in the columns would be liable to burst the tanks, unless these were made exceedingly strong.
Indeed, it is always better to have separate boilers where two objects are to be served, as in such a case as this. In ornamental conservatories, such as this is, when intended for tropical plants, it will be found exceedingly useful to have elegant vases distributed through it At times these may be occupied with single specjmen plants, but their legitimate use is to act as reservoirs of hot water, to be supplied by small pipes passing up through them, and not only to give out heat by radiation from their sides, but vapor from their tops. Vases, however, for this purpose, should be metallic, as giving off heat more rapidly than stone, composition, or earthenware; and care should be taken that they associate with the style of architecture of the house.
In defining wherein the conservatory differs from the green-house, we have said above that, in the former, the plants or trees are planted out in a border of prepared soil. This, however, is not absolutely necessary, nor at all times expedient The trees or plants flay be grown in large tubs, boxes, or pots; but as these are in general unsightly, they may be set in a floor sunk under the level of the walks, and elevated or lowered according to the depth of the tub, box, or pot - the space above being covered with portable panels of cast-iron grating of ornamental pattern, so as to form, when arranged, a very complete flooring. Or the boxes may be plunged, or covered with stones, flints, brickbats, coarse gravel, etc., to within a few inches of the floor level, and finished off with a covering of clean gravel, moss frequently renewed, or any other similar contrivance, to hide the cases in which the trees are planted - leaving, however, the surface of the soil exposed to view, for the purpose of watering and for the admission of air to their roots.
By these latter means they will appear as if planted out in the general effect, but, at the same time, be capable of removal when fresh arrangements are deemed expedient, or of being taken to some other house in the event of sickness, or totally removed to give room to others more valuable. When the stronger and more robust-growing plants are planted in a bed of prepared soil, which is in general, in conservatories, made too rich and too deep, they outgrow all bounds; even the house itself is not sufficient to contain them. They injure or destroy their less vigorous, and, very often, more valuable neighbors; and, after a year or two, they themselves have to be cut out and thrown away, after having destroyed all around them, by overshadowing them, and robbing them of their share of nourishment at the roots. By confining them to large tubs, boxes, or pots, the latter of these evils is completely remedied, their extra luxuriance is checked, a disposition to produce more flowers, in proportion to their size, is brought on; and often, in summer, some of the more hardy may be set out of doors, to give breathing room, as it were, to the others; and when the house becomes too much crowded, the duplicates, or those least interesting to the proprietor, may be removed altogether, and disposed of in a variety of ways.
It is quite absurd in this country to attempt to grow the trees of the tropics, or even of extra-tropical countries, to anything like their natural size. Who would be so bold, let us only ask, as to construct a house in which a single plant of Araucaria excelsa could develop itself to even half its natural size? or who would find accommodation for a full-grown tree of Adansonia digitate, the very trunk of which, if we are to believe travelers, is equal to the diameter of almost the largest glass-house built in Europe? As it is therefore quite impossible for us to exhibit the trees, and, indeed, many even of the herbaceous plants of distant countries, of their full natural size, let us be content to raise them as it were by scale, and, by good cultivation and proper accommodation, cause them to develop their natural character somewhat diminished from the original in dimensions.
A correspondent of the Horticulturist inquires, if conservatories or greenhouses attached to dwellings can be made successful I can answer affirmatively, as I have had the management of one for many years so situated. This green-house is attached to the dwelling in the angle formed by the main house and back building, facing south, with the parlor windows and hall door opening into it The roof is of tin, supported by pillars, in which the sash are made to fit, so that they may be removed in summer, leaving an open piazza. There are outside shutters. The floor is of brick, which enables you to use water freely, and retains a proper degree of moisture throughout the house. It is heated by a small coal-stove of cast-iron, which consumes about a quarter of a ton of coal during the winter. Hardy green-house plants do perfectly well here, such as Lemon and Orange trees, Laurustinus, Myrtle, Sweet Bay, Jasmins, Camellias, Rhododendrons, Pelargoniums, Coronellas, Primulas, Oxalis, Violets, Wall Flowers, and Stock Gillies. Many of the annuals, also will bloom beautifully in the spring. I call these plants hardy, as I have had, occasionally, two or three degrees of frost in the house without injury.
I consider a fire only necessary when the thermometer is likely to be below 20 ° out of doors. I have never perceived any dampness or unheal thiness to proceed from this house. On the contrary, it is delightful to see from the parlor windows, in cold winter weather, the Lemon trees loaded with their beautiful golden fruit, and rich dark-green leaves ; and then you have the odor of the Laurustinus, Mignonette, Violets, Stock Gillies, and other sweet flowers, diffused through your dwelling.
This is, I think, the cheapest and most convenient way of having a green-house attached to your dwelling. The expense may, of course, be increased indefinitely and without any ill effects, either from dampness or unhealthiness. H. N. Johnson. - Germantown, Pa.