THE GREEN-HOUSE AND CONSERVATORY. 



23 



This might be much reduced by making the back wall of 

 wood, instead of brick, and sheathing it inside ; but it 

 would not be so warm, and in the end would be more 

 expensive, as it would, after a few years, require constant 

 repairs. 



FIG. A. 



Most of the houses of florists who raise flowers for 

 the market are not properly green-houses, but pits ; that 

 is, they are excavated from two to four feet below 

 the surface of the ground, and the roof laid on very low, 

 so that a great saving of heat is effected. The dampness 

 is congenial to the plants, which often thrive wonderfully ; 

 but these structures, being cheaply built, soon fall to 

 pieces. As a general rule, in all horticultural structures, 

 every part which is to come near, or in contact with, the 

 ground, should be of stone or brick ; and, carrying this 

 principle still farther, the less wood work we have, the 

 better. 





