Page:The Amateur's Greenhouse and Conservatory.djvu/48

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chiefly. We preferred to heat the houses in the orthodox fashion, and selected for the purpose one of the upright conical boilers of the Thames Bank Company, and left Mr. Dunbar to fight it out, and the result of his operations was that the lower house was heated with four-inch flow-and-return placed side by side in the front of the house, on a dead level, and from these heat enough was derived to keep all safe in severe frosty weather. The figure will show that the Paxtonian stands slightly above the level of the lean-to; so we had but to make sure of a fire in the furnace, and the heating of this house was an easy matter. The pipes had, however, to be taken a distance of twenty-five feet from the furnace to the Paxtonian; and, as this would cause a great waste of heat, a long, trough-like wooden box was fitted to the dwarf wall on which the pipes rested, and they were thus enclosed from the weather. The box was covered with stout shutters clothed with felt, and it became immediately a dark forcing pit, and has been used ever since, during the winter and early spring, for forcing sea-kale, asparagus, rhubarb, &amp;c. The pipes in this box are of two inches bore, to cause a quick flow, and make the waste of heat the least possible; but, as soon as they enter the house, they are enlarged to four inches, and thus they pass all round the house,