64 OPEN AIR GKAPE CULTURE. 



branches themselves, placed one above the other, so 

 that none but the uppermost branches which radiate 

 into space will feel its full effects ; but when a cold 

 wind is constantly passing through the branches and 

 among the flowers, the perspiration — against which 

 no sufficient guard is provided by nature — beoomes 

 80 rapid as to increase the amount of cold consider- 

 ably, besides abstracting more aqueous matter than 

 a plant can safely part with. To prevent this being 

 one of the great objects of training trees, it is incon- 

 ceivable how any one should have recommended 

 such devices as those mentioned in the ' Horticultural 

 Transactions,' 11. Appendix, p. 8., of training trees 

 upon a horizontal plane; the only effect of which 

 would be to expose a tree as much as possible. to the 

 effect of that radiation which it is the very purpose 

 of training to guard against." 



All terraces should be well drained, and the drains 

 are best arranged by having a series of cross drains 

 parallel to the terrace, as seen in section fig. 4 and 5, 

 and emptying into a main drain which descends the 

 hill. These drains should be placed as in the figures, 

 taking care to leave the ground under the wall solid 

 and undisturbed. In forming terraces for vine cul- 

 ture it is necessflry to exercise care and judgment, so 

 as not to bury the good soil and leave the poor soil 

 for the vines to grow in. 



