158 APPLICATION OF PRINCIPLES. 



was afforded. By means of stakes and bandages of 

 hay, not so tightly bound as to impede the progress 

 of any fluid within the trees, I nearly deprived the 

 roots and lower parts of the stems of several trees of 

 all motion, to the height of three feet from the ground, 

 leaving the upper part of the stems and branches in 

 their natural state. In the succeeding summer, much 

 new wood accumulated in the parts which were kept 

 in motion by the wind ; but the lower parts of the 

 stems and roots increased very little in size. Remov- 

 ing the bandages from one of these trees in the fol- 

 lowing winter, I fixed a stake in the ground, about 

 ten feet distant from the tree, on the east side of it ; 

 and I attached the tree to the stake at the height of 

 six feet, by means of a slender pole, about twelve 

 feet long ; thus leaving the tree at liberty to move 

 towards the north and south, or, more properly, in 

 the segment of a circle, of which the pole formed a 

 radius ; but in no other direction. Thus circum- 

 stanced, the diameter of the tree from north to south 

 in that part of its stem which was most exercised by 

 the wind exceeded that in the opposite direction, in 

 the following autumn, in the proportion of thirteen to 

 eleven." 



Now, if the effect of motion is to increase the 

 quantity of wood in a plant, it is evident that ventila- 

 tion, which causes motion, must tend to produce a 

 healthy action in the plants exposed to it; and such a 

 state must also be favourable to the developement of 

 all those secretions upon which the organisation of 

 flowers, the setting of fruit, and the elaboration of 



