PLANT-HOUSES. 477 



on account of the small space to be heated, and the large surface exposed to 

 the external air. We have already mentioned the practicability of heating 

 such places from the kitchen fire, or from a fire or boiler placed in another 

 story ; and suggested, at the same time, that the necessary pressure on the 

 boilei's, or the tubes, rendered this mode of heating by no means advisable. 

 It is also a fact, that in some places sufficient warmth may be given to the 

 plant cabinet by opening the door of the sitting-room communicating with it 

 the last thing before the family retire to bed, and leaving it open all night. 

 On the whole, we are of opinion that the best mode of heating plant cabinets, 

 or small green-houses attached to dwellings, is by some source of heat on 

 their own level; and not from any source either above or below. If no flue 

 has been built in the wall of the house suitable for carrying off the smoke 

 from any stove or fireplace made in the plant cabinet, a tube of cast or sheet 

 iron, or of earthenware, may be partially sunk into the outer face of the wall 

 of the house; and disguised by a projection so designed as to be consistent 

 with the architectural character and efiect of the elevation. In some places, 

 tubing of this sort may be placed against the wall, and covered with an 

 architectural case of boards, metal, or slates, painted in imitation of stone ; 

 and sometimes these projections admit of being disguised by common ivy, or 

 the Virginian creeper. At all events, no architect of the slightest degree of 

 ingenuity will be at a loss to discover the proper situation for a circular flue 

 of 3 in. in diameter; and no builder who has any regard either for appear- 

 ances, or the free ascent of the smoke, in such a fiue, will ever put it up with- 

 out a casing to give it architectural effect, and to serve as a nonconductor, 

 and thus to preserve what may be called a lining of heat round it, to favour 

 the ascent of the smoke. The situation for the flue having been fixed on, 

 the next thing is to determine the mode of heating ; and this, we are of 

 opinion, ought, in most cases of small plant cabinets, to be by a hot- water 

 stove placed within the cabinet, and heated by a register fire-pot within, like 

 that of Dr. Arnott. The fuel used may be coke on ordinary occasions ; 

 anthracite when a greater heat was wanted ; and, perhaps, charcoal in the 

 most severe Avinter nights, when the heat required was very considerable. A 

 stove of this kind, properly constructed, may be kept burning night and day, 

 regulating the admission of air to the fire according to the heat required. For 

 this purpose, the stove may either have a hand regulator, as in the imitations 

 of Dr. Arnott's stoves, a thermometer one being unnecessary ; or, in order to 

 insure a draught, the air may be brought to the stove by a leaden pipe of 1 in. 

 in diameter within, from a lower level, either immediately under the house, 

 or from the open air ; or from any place from which it is desirable to extract 

 the air for the purpose of ventilation. In all these cases, the air admitted to 

 the fire may be regulated by a common stopcock, like that in use for common 

 water-pipes. We think it not unlikely that the smoke, or products of com- 

 bustion, where the kind of fuel we have recommended is used, might be con- 

 veyed away in a horizontal direction, or perhaps even downwards to a drain, 

 in a tube of not more than double the diameter of that used for supplying air to 

 the fire; but, never having seen this mode put in practice, we cannot venture 

 to recommend it. We have seen the common smoke-flues of hotliouses dis- 

 charge their smoke horizontally, but it is always attended with a waste of 

 heat. 



524. Heating with hot-water, — The mode in which water is heated by a 



