Mr. Willmot's Gardens, Isleworth.- October 3. Having seen the chunk-stove advertised as being used by Mr. Willmot with great advantage, we called to see it. The stove is small, portable, placed within the house (a vinery), and burns only coke or cinders. The fire is placed in one cylinder, which is surrounded by another, and the air, which enters at the bottom and passes up the space between, being there heated, is distributed along the front of the house in two perforated tubes proceeding right and left from the stove. The fuel is supplied from the top by a very ingenious contrivance, viz. a box the bottom of which is fitted exactly to the upper orifice of the fuel chamber; and being filled with fuel, the bottom, which slides in grooves, is drawn out, and the fuel is dropped into the fuel chamber without the admission of smoke or dust into the house. Before the fuel box is removed, the cover of the fire chamber, which also slides in grooves, is pushed in and thus replaced. The smoke from the coke or cinders passes through the front wall of the house in a sheet-iron tube of about 3 in. in diameter, and the hot-air tubes are of the same material and dimensions. To counteract the effects of the dry heat produced, a tin tray filled with water is placed over each tube, so as to be in contact with it and evaporate the water. There can be no doubt but that this is a very economical mode of heating, not only with reference to the first cost of the apparatus, but to the daily cost of the fuel; but it has two disadvantages. In the first place, the dry heat produced is unfavourable to vegetation, and cannot easily be rendered moist, because the heat issues in the form of streams of hot air; and not by radiation, from the surface of heated tubes, as in the case of smoke, water, or steam, confined in flues or pipes: and, secondly, should the fire be stronger at any time, from any accidental circumstance, such as better cinders or coke being used, or the smoke funnel and the inside of the furnace being newly cleared out; or should a very mild night unexpectedly occur; then the quantity of heated air suddenly produced will be so great as to overheat the house, and greatly injure the foliage of the plants. On the other hand, if the fire were to go out unexpectedly, there is no sufficient reservoir of heat, as there is in the case of flues or hot-water pipes; for the heat in the fuel, after the fire is gone out, is rapidly carried off by the circulation of the air. We admit that, by great care on the part of the gardener, this may be mitigated; but, from the mode being liable to accidents of this kind, it cannot be generally recommended. For heating a house or pit where there are no flues or other means of heating, it may become a useful expedient. However, if we have not done justice to this mode of heating, we are open to the corrections and reasoning of Mr. Willmot.
