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rigorous weather, when the heat of their dung-casings is declining, they are, as it were, almost at the peril of their plants, dared to touch it, for fear of increasing the evil; they know at any rate that if, at an immense sacrifice of labour, they do succeed in replenishing it piece by piece, it is at least two or three days before it is again in a proper and effectual state of action; and even this period will be lengthened, if they have not on hand a plentiful supply of materials ready for use: they must know likewise, even though they may never have had the benefit of experiencing it, that a fire could be made up, and would produce the effect required, by means of the tank, in as many hours as it would take days to do so by following the old plan. And mark this — for it is a point of the utmost importance — the tank system will effect this: thus much can now be very safely asserted.
We sometimes hear of the more humid kind of heat given out from hot-water pipes than is the case with other appliances, such, for instance, as a flue. It is not unfrequently asserted, that the heat thus imparted is so moist, so genial, so peculiarly adapted to plants. Without doubt, the heat thus obtained is infinitely more suited to the development of plants than that derived from a flue: but its superiority consists in its purity, that is, its freeness from noxious gases, and not in its possessing a greater degree of moisture; the pipes are composed of a material not to any extent porous, and they give off the caloric only, which is transmitted from the fire to the water, from the water to the pipes, and from these latter to the atmosphere; it is next to impossible to conceive any thing more thoroughly devoid of moisture than the heat thus communicated to the atmosphere. On the other hand, flues are constructed of porous materials, and smoke, which contains a considerable portion of the elements of water, penetrates more or less through them, and thus the heat imparted from a flue, except where it is in immediate vicinage to the furnace, or direct source of caloric, will be found to be certainly not less, but in a degree more, humid than that from hotwater pipes. Its impurity, however, renders it far less desirable; for moisture can be added to the dry heat of hot-water pipes.
The engraving will perhaps be rendered more intelligible by a few descriptive remarks, in addition to the reference to the letters. First, I would say that the house should be provided with a tank near the front, in which a circulation of heated water would supply a genial warmth to the soil and the roots: attached to the same boiler which heated the water
a, Ground level. b, Pathway. c, Lowest point excavated, on which a bed (o) may be made for rhubarb, &c. d, Tank, supported by brick piers (p). e, Pipes for the supply of atmospheric heat. /, Apertures for the admission of air, which passes through the chamber g, into the tank, by a series of openings at A, and thence into the house by the tubes m, escaping through the ventilators i. m, Bed of soil on which the plants grow.
in this tank, a series of pipes might be so arranged as to supply heat to the atmosphere above the tank, which would be constructed so as to be as near the glass as circumstances would admit: a shallow bed of soil would be placed, resting on a due portion of open rubble for drainage; the upper surface of the tank would be rendered level, so as to admit of water being poured in quantity among the loose drainage, which would ultimately, by the agency of the heat below, be induced to rise among the soil in the form of vapour, and thus duly supply it with moisture. Beneath the tank, an open space would admit of mushrooms or rhubarb, &c, being cultivated with facility. The admission of air would be provided for by apertures through the front wall, communicating with the upper part of the tank above the level of the water; from thence small tubes would rise at intervals through the soil into the house, and this might be opened or closed at pleasure; the outer orifice would be provided with small sliding shutters, to exclude the external air when not required. By this arrangement the cold air would pass over the surface of the heated water, and become not only warmed in its progress, but also supplied with an amount of moisture proportionate to its rarefaction, and the evil resulting from the admission of cold dry air will thus be altogether prevented.
The plants would be trained on a trellis placed about 15 inches from the glass, and their roots would be confined to certain portions of soil, which would from time to time be replenished. This might easily be accomplished by various arrangements; a few slates placed about each plant would serve as one simple means of effecting it. Transverse divisions would be introduced so as to allow of the removal and renewal of a plant and its soil without disturbing its neighbours; a complete succession might thus be effected. The structure itself would exteriorly be covered with shutters of light frame-work, covered with painted or tarred canvass. These would be kept about six inches from the glass, and thus a cavity would be formed, the air contained in which would serve to prevent that incessant drain upon the temperature of the house which takes place either when the covering is in contact with the glass, or when altogether absent.
Next in importance and usefulness to a house such as I described, I would recommend a pit heated in a similar manner, as being equally suited to accomplish the end in view, though somewhat less convenient in its application to practice. The principal difference between the house already referred to and such a pit would be the omission of the pathway at the back; and that the tank would occupy the whole width of the pit, except, perhaps, a cavity of six inches on either side, or else (which would be equally effectual) the improvement already described in this work might be adopted. The plants would be trained on a trellis near the glass, and be grown in shallow beds of soil above the tank.
Planting.—I may here take occasion to mention that a small portion of soil only should be employed at the time of planting; for if the whole of what is made use of were placed at once in its appointed situation, it might be subject to become soured by the constant action of the atmospheric humidity; at any rate it would be preferable not to risk such a possibility. The portion employed and from time to time added, may be kept together about the roots by means of two or three common slates placed about it. Instead of raising the plants in pots, and transplanting them to these little hillocks of soil, I would would prefer sowing the seeds at once where it was intended they should grow. The tissue of which the roots of cucumbers are composed is of a very succulent and tender nature, and is liable to sustain a serious injury, even by the most careful act of transplantation. This mutilation would have the effect of checking the growth and development of the plants—a result which no care should be withheld which could possibly have any influence to prevent. The development and fructification of plants, all other circumstances of growth being favourable, will be in proportion as the elements of their vitality and extension are uninterruptedly supplied; and, all other circumstances being equal, the result of injury sustained by the organs of nutrition, or of a diminution of food, will be to retard the ultimate perfection both of development and fructification. To carry this principle into practice, I would propose that these hillocks of soil should be made of the same height as the thickness of the soil was intended to be; on this I would invert a 60-sized pot, having the bottom neatly taken out, and this should be filled with soil in which to sow the seed. After vegetation, the roots would penetrate and ramify into the soil beneath, whilst the inverted pot would still remain about the neck of the plant, where it would serve to protect it from injury, either in watering, in adding fresh soil, or from any accidental causes. It will be an advantage, whilst the plants are young and there is no risk of injuring the roots, to stir the soil very lightly every day, so as to keep all clean and neat about them, and prevent the growth of fungi, which are during winter ready enough to rise into being; it will also prevent the surface from becoming caked, and thereby rendered impervious to the action of the source of light and heat.
Pruning. — The plants being intended to occupy a surface of trellis-work near the roof, it will be requisite to encourage their leading shoots to a length sufficient to reach it; when this point is gained they should be " stopped," and thus induced to produce lateral branches; these should be disposed at regular distances on the trellis in a direction towards the top of the house. When they have grown about half-way, they each should also be " stopped," and this will produce several new ramifications of the stern. The uppermost one, if vigorous and healthy, should be trained upwards towards the top of the house, and the others should receive a lateral direction; if these do not show fruit at the second leaf from the main branch they must be stopped again, and this operation should be continually repeated at every leaf until fruit is produced; the upper part of the house should have the same kind of treatment. When fruit blossoms are perceived, the branches on which they occur should be permitted to extend until after the flower has expanded, with a view of leading up a suitable, but not accumulative, supply of food at that delicate period; after this the branch should be stopped at the next leaf beyond the fruit; this will throw in a more abundant supply to that particular part, which is now performing functions peculiarly its own, and which require to be properly supported and encouraged: the leaf beyond will serve as a reservoir to receive the surplus supply, and as a laboratory to purify and assimilate that which reaches it, and return its appointed portion towards sustaining the consti. tutional vigour of the plant.
This system of pruning must be continued whilst the branches continue in a bearing state, but when any symptoms of decay or of expended powers are perceived, they may be pruned quite away, and young and vigorous branches encouraged in their stead. All this pruning, except that of removing the main shoots, should be done at a sufficiently early period of growth; to be effected with the thumb nail ; for, like all other plants, cucumbers are best treated when whatever pruning they require is performed when the least amount of trouble and labour is required to perform it. It is better to remove a portion of any plant at an early period of its growth, and thus to economise its vital energies, rather than to suffer them to be expended, and the supply to become exhausted through a superfluous development, and then to deprive it of the very organs by the action of which the expenditure would be again recompensed to the vital energies.
Season.—But little can be said as to the exact time at which