316 Memoirs of the Caledonian Horticultural Society. 



wall, as the reflection of the sun's rays upon it, which brings 

 fruit to perfection. These walls might be erected in gardens 

 in many different ways : they would look very well in front of 

 a hedge, and the space underneath might be used as a mush- 

 room house, a tool shed, or a storehouse for culinary roots 

 during winter. Banks of earth might even be thrown up, 

 and, after being paved with stone, and plastered, might be 

 used as inclined walls. Steep terrace banks might also answer 

 the same purpose." 



In training fruit trees it should be a principal object to im- 

 prove their climate ; but the mode of training and pruning too 

 generally in use at present is, in this respect, very defective. 

 " By a constant cutting off of breast wood, especially in pear 

 trees and the finer sorts of apples, and of course a continual 

 provoking of the tree to push out more, the spurs become 

 soon of an enormous length, and consequently the fruit they 

 produce must hang at a considerable distance from the wall. 

 Now, it can be proved, by applying a thermometer, that, at 

 the distance of several inches from the wall, the air is not 

 hotter than the general air of the garden ; and hence the evil 

 of which I complain. It is not, indeed, uncommon to see the 

 spurs of an old tree standing out like the teeth of a rake, or 

 the bristled face of a cut hedge : nor is it to be wondered at 

 that the fruit of such trees should be always small, and never 

 well flavoured." 



Nothing can be of greater importance in the training of 

 wall fruit trees than nailing their spurs close to the wall. 

 " In my opinion, it is owing neither to age, nor deficiency of 

 soil, that many trees bear such small trifling fruit, but to an 

 injudicious mode of training and pruning ; and, instead of 

 complaining that the spurs of a tree are too old, I would con*- 

 sider it rather an advantage to have old spurs, since the fruit 

 of old trees, and of old wood, is sooner ripe, and much higher 

 flavoured than that of young ones, provided always that it can 

 be made to grow equally near the walls. 



" In order to prevent young trees from running into a num- 

 ber of rough unmanageable spurs, the leading branches should 

 never be laid in closer than from one to two feet apart, and 

 then the intermediate spaces may be filled with bearing spurs, 

 which, I once more repeat, ought to be always closely nailed 

 to the wall." 



In a PS., dated a year afterwards, Mr. Henderson in- 

 forms us that he finds the difference of temperature between a 

 sloping and perpendicular wall to be generally about 20°. 

 Such walls might be framed of timber, plastered with Roman 



