128 



OPEN AIR GKAPE CULTDKE. 



tal limit to this law — that is, that the distance to 

 which the sap may he propelled exceeds any limits to 

 which it is ever necessary to carry it. 



" If the shoots of the vine are trained along a con- 

 siderable extent of wall, the branches spread out much 

 wider, and the berries attain a larger size. This 

 property of the vine, although known to experienced 

 gardeners, is not taken advantage of as it ought to be. 

 A vine might be trained horizontally under the cop- 

 ing of a wall to a great distance, and by inverting tlie 

 bearing shoots, the spaces between the other fruit- 

 trees and the top of the wall could readily be filled 

 np, and if different vines were inarched to the hori- 

 zontal branch, the south wall of a large garden might 

 be furnished with a variety of sorts from the stem 

 and root of a single plant, the roots of which would 

 not encumber the border in which the other fruit- 

 trees are. growing. I have an experiment of this kind 

 now in progress in my garden. Within a few years 

 past, 1 have gradually trained bearing branches of a 

 small black cluster grape, to the distance of near 

 fifty feet from the root, and I find the bunches every 

 year grow larger, and ripen earlier as the shoots con- 

 tinue to advance. 



" According to Mr. Knight's theory of the circula- 

 lation of the sap, the ascending sap must necessarily 

 become enriched by the nutritious particles it meets 



