72 ON PRUNING. 



woiild be unable to bear a very moderate gale. 

 The lower, or balancing boughs, through 

 bending towards the earth, receive the wind 

 upon their upper surfaces, and its effect on 

 them is converted directly to support the tree; 

 for the direction of the force of the wind is 

 at right-angles with the surface it strikes, it 

 therefore presses the limb next the wind to- 

 wards the ground, and of course the stronger 

 the wind blows, the firmer is the tree by these 

 limbs held to the ground ; and if these ba- 

 lancing limbs be all perfect, it is almost im- 

 possible the tree can be blown up by the 

 roots; the stem would sooner be broken off 

 above the balancing limbs. How much the 

 stability of the tree is increased, too, by having 

 its centre of gravity by these large and heavy 

 boughs brought so near the ground ! Although 

 so amply provided with the power of evading 

 the wind, yet it is sujGR.ciently provided with 

 strength to resist it. 



" There is great reason to beheve that the 



