362 



PLANT-HOUSES. 



fig. 500, which support the roof, into a 



large tank under the portico, and brought 



_ up again by a for- 



Fig. 500. • ° J o xi 



cmg-pump for the 



supply of the 

 house." 



Those parts of 

 the roof immedi- 

 ately over the 

 walks are covered 

 with double plates 

 of iron enclosing 

 a body of air, to 

 prevent the escape 

 of heat; and over 

 these are neat iron 

 gratings, so that any 

 one may walk along 

 to repair the glass, 

 paint, &c. Ventila- 

 tion is effected by 

 opening the windows in front or at the 

 ends, and by letting down the top roof 

 sashes. It is heated by a combination of 

 Sylvester's hot-air stove and steam placed 

 in chambers under the floors. From the 

 manner in which the roof of this house is 

 constructed, it will readily be understood 

 that any extent of area may be enclosed ; 

 and, in this respect, it approaches very 

 closely to the more recently invented 

 ridge-and-furrow roof. In the latter, no 

 doubt, half the number of columns would 

 suffice, both for supporting the roof, and 

 also for taking away the rain water; but 

 the number of these is no disadvantage, 

 as climbing plants constitute so large a 

 portion of conservatory decoration, and 

 as, for want of such conveniences to train 

 them to, they are much less cultivated 

 than they deserve ; for amongst them 

 some of the most beautiful and profuse 

 bloomers are to be found. 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 centre of the 

 column, and descending down the sides. 

 The heat, by this means, would be radi- 

 ated to all parts of the house. The con- 

 ducting pipes, both for the flow of the 

 hot water and its return towards 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 re- 

 quired. These could easily be regulated 

 by proper stopcocks placed on the mains, 

 and could be reached by having orna- 

 mental 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 amongst 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 specimen plants, but their legiti- 

 mate use is to act as reservoirs of hot 

 water, to be supplied by small pipes pass- 

 ing up through them, and not only to give 

 out heat by radiation from their sides, but 

 vapour 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 greenhouse, we have said 

 above that, in the former, the plants or 

 trees are planted out in a border of pre- 

 pared soil. This, however, is not abso- 

 lutely necessary, nor at all times expedient. 

 The trees or plants may 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 com- 

 plete flooring. Or the boxes may be 

 plunged, or covered with stones, flints, 

 brickbats, coarse gravel, &c, to within a 

 few inches of the floor level, and finished 



