ON THE CONSTRUCTION OF WALLS. 63 



after they have become ripe. They also contribute 

 to prevent the escape of heat from the wall, and are 

 likewise extremely convenient to fasten netting, bun- 

 ting, &c. to, when necessary to protect the frnit from 

 birds and insects. On the other hand, they exchide a 

 portion of light and air, and prevent the dew and in 

 some measure the rain also, from descending on the 

 foliage, and these are very beneficial after the fruit is 

 set, and until it begins to ripen. Nevertheless the ad- 

 vantages of projecting copings decidedly preponderate. 

 If there were no other benefit arising from them, that 

 of protecting the fruit from heavy rains, and thereby 

 keeping it dry and in good condition, for two or three 

 months after it is ripe, would be quite sufiicient to 

 turn the scale at once in their favor. With respect to 

 the width of the projecting part when permanently 

 fixed, that must depend on the aspect and height of 

 the wall. If the latter be less than four feet, and the 

 aspect south, the coping ought not to project at all, 

 as the light and solar heat excluded by it, will be a 

 serious drawback on the healthy vegetation of the 

 vines. But if the wall be four feet high, then the 

 coping may project as many inches, and if this width 

 be increased an inch every foot that the wall increases 

 in height up to twelve feet, the principal advantages 

 arising from the protection which a coping aftbrds, 

 will be secured, in conjunction with the smallest 

 portion of its disadvantages. If the wall therefore be 

 twelve feet high, the coping will project a foot, more 

 than which no coping should project, whatever may 

 be the height of the wall. If the aspect be casi or 

 uwst, the coping must be as narrow as possible, as 

 every inch of projection in these aspects, causes a 

 considerable diminution in the duration of sunshine 

 on the surface of the wall. If the height of the wall 

 be less than six feet, a projection had better be dis- 

 pensed with, but if it reach that height, one of four 

 inches in width may be used, and this may be in- 

 creased half an inch every foot the wall is higher, 

 until it reach the width of twelve inches, which will 



