190 



FIXED STRUCTURES FOR GROWING 



under the glass, and partly on the back wall. In either case, the nar- 

 rower the house the more readily is it heated either by fire or the 

 sun. As these details vary with the kind of trees and plants to be 

 forced, they belong more properly to the following part of this work. 

 See ' Practice of Horticulture, Forcing-Garden.' 



Fig. 155. 



Half -span forcing-house. 



A Plant-structure for all or any of the above Purposes. The pit, 

 fig. 151, or that shown in figs. 153 and 154, will answer for any 

 one of the purposes for which orangeries, greenhouses, and stoves are 

 erected. Orange-trees and similar plants, in a dormant state, may 

 be preserved through the winter in such pits with ample coverings, 

 and scarcely any artificial heat ; greenhouse plants, with very little 

 heat ; dry stove-plants, with a little more heat ; damp-stove plants, 

 with increased temperature and moisture ; other stove plants, till they 

 attain a certain size ; pine-apples, to the highest degree of perfection ; 

 and the fruit-trees trained to trellises under the glass may be forced, 

 as may be also every description of culinary vegetable, not excepting 

 mushrooms, which may be grown in a portion of the bark -bed, or in 

 shelves against the back wall or in arched recesses, or cellars, or vaults 

 under the tan of the pit. In short, there is nothing in the way of culture 

 that may not be carried on to the highest degree of perfection in these 

 pits, provided that all the large-growing plants are trained on trellises 

 close under the glass ; but the airy elegance of the greenhouse, the gran- 

 deur and picturesque luxuriousness of the conservatory, and the tropical 



