WALLS. 151 



and the soutliern aspect of the south wall shouhl he 

 made available by means of a piece of enclosed gromid 

 in front of it : when this is not an object of much con- 

 sequence, a square, or some other more varied form, 

 may be selected. 



The Walls. — The height of the walls should have 

 some proportion to the size of the garden. They may 

 vary from eight to sixteen feet : below or above these 

 heights they are neither convenient nor useful. For 

 these walls, well-made and well-burnt bricks are cer- 

 tainly the best materials, being most kindly to the 

 growth of trees, and affording the greatest facilities for 

 training them. We have often, however, had walls 

 erected in whole or in great part of stones ; and when 

 the stones were good, and kept down to a proper size, 

 we have found the walls little inferior to those composed 

 of brick. In good gardens a considerable portion of 

 the best walls should be constructed with flues and 

 furnaces, so that they may be artificially heated in 

 spring and autumn — in spring to protect the blossom, 

 and in autvmin to aid in maturing the fruit, and what 

 perhaps is of equal importance, to ripen the fruit- 

 bearing wood for the following year. We may add, 

 though the remark perhaps belongs to practical horti- 

 culture, that in autumn artificial heat is often applied 

 only dming the night. This is improper ; for light, a 

 main agent in perfecting vegetable life, is then absent. 

 When the fire -heat is employed diu'ing the day, it co- 

 operates 'v\ith the solar heat and light in the elaboration 

 of the juices of the fruit and foliage, and its action may 

 be equivalent to the reduction of several degrees from 

 the latitude of the place. Good flues, with proper fur- 

 naces attached, have been found to be superior to hot- 



