40 ON ASPECT. 



enjoy the full effects of the solar and atmospherical in- 

 fluence, that an extraordinary supply of sap is required, 

 to rise every instant of time throughout the growing 

 season, to enable it to recruit its loss. On the foliage 

 of a plant performing some of its most important func- 

 tions in such a manner, if a strong wind should blow 

 at any time for the space only of a few hours, the flow 

 of sap is seriously checked, evaporation proceeds at a 

 most exhausting rate, and the leaves and young shoots 

 being speedily emptied of the moisture accumulated in 

 their cells and vessels, become rigid, and their pores 

 completely closed. The vegetative powers of the 

 plant being thus prostrated, cannot resume their func- 

 tions till after the wind has ceased for several hours, 

 or even days, according to its previous violence and 

 duration. 



I have made repeated observations on the growth of 

 the leading shoots of vines in the height of the growing 

 season, and have many times noted the fact, that dur- 

 ing the space of twenty four hours, when the wind has 

 blown briskly, the shoots exposed to its influence have 

 not perceptibly grown at all ; while, shortly afterwards, 

 the wind having entirely sunk away, the same shoots 

 have grown upwards of three inches in a similar space 

 of time, the temperature of the air in a sheltered situ- 

 ation being alike during each period. 



And if two young vines be planted by the side of 

 each other, against a wall exposed to the north, for the 

 purpose of trying the experiment, by excluding the 

 influence of the sun's rays, and one be kept nailed to 

 the wall, every five or six inches of its growth through- 

 out the summer, and the other be suffered to be blown 

 about without any such protection, the former will 

 be found, at the end of the season, to have grown in 

 the size and extent of its shoots three or four times 

 as much as the latter. Nothing, indeed, can be more 



