WALLS AND TRELLISES. 159 



exposed trellises. The wood also is more perfectly 

 matured, and this, during a succession of years, exerts 

 a considerable and favorable influence on the vine. 



The effect of walls doubtless depends "upon two 

 causes, one being the higher temperature produced 

 by the radiation fi^om the surface of the solid wall, 

 and the other being the protection from wind and 

 storms which such a structure affords. 



That the latter point is one of material importance, 

 we are well satisfied, for however essential ventilation 

 may be to the healthy growth of the vine, all violent 

 winds and cold blasts are to be studiously avoided. 



A striking instance of this is to be seen in the gar- 

 den of a gentleman of this city. Several vines are 

 there trained along the east side of a high board fence, 

 and although the same judicious and systematic care 

 is given to all parts of the vines, yet the finest fruit is 

 uniformly found a foot or two below the top of the 

 fence. ISTow when we remember that on all open 

 trellises the finest grapes are found at the top, since 

 all trees produce the best fruit at the extremities of 

 the branches, we must attribute no mean effect to the 

 protection afforded by the fence, since the boards of 

 which it is composed can scarcely be supposed to 

 retain and radiate much heat, and its heiglit (about 

 eiglrt feet) is not sufficient to include the limit to 

 which vines may be judiciously carried. 



