68 ON THE CONSTRUCTION OP WALLS. 



frosts in the spring, in preserving the blossoms from 

 cold dews and heavy rains, and in keeping the grapes 

 in good condition, for a considerable period of time 

 after they have become ripe. They also contribute to 

 prevent the escape of heat from the wall, and are like- 

 wise extremely convenient to fasten netting, bunting, 

 &c. to, when necessary to protect the fruit from birds 

 and insects. On the other hand, they exclude a por- 

 tion 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 advantages 

 of projecting copings decidedly preponderate. If there 

 were no other benefit arising from them, that of pro- 

 tecting 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 sufficient to turn the 

 scale at once in their favour. 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 protec- 

 tion which a coping affords, will be secured, in con- 

 junction 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 east, or west, the coping must be as nar- 

 row as possible, as every inch of projection in these 

 aspects, causes a considerable diminution in the dura- 



