68 THE WHEAT CULTTJRIST. 



crowbar, understands something of the force required by 

 plants to spread through the hard soil. In many locali- 

 ties a wooden staff can be thrust into the ground three 

 or four feet deep, with a very little force. On the con- 

 trary, in most localities, it is exceedingly difficult to 

 work a crowbar through the soil. What a powerful 

 force must necessarily be exerted, then, by a plant, 

 in pushing its roots through the hard soil. "We frequent- 

 ly have ocular demonstration of the force exerted by 

 small plants and trees. It is a common occurrence, 

 where the soil is heavy, to see a crust of earth, that is 

 formed over the growing stems, to be lifted up, so that 

 the young stems appear above the surface of the ground, 

 often throwing off a crust of earth more than ten times 

 heavier than the entire plant would be, were both weigh- 

 ed in a balance. Then, there is the exercise of a con- 

 stant force to keep the plant in an erect position. In 

 many instances, the force of gravity on the growing 

 plant exceeds the vital force exercised in developing the 

 various parts and keeping the stem erect. When this 

 is the case, stems fall to the ground before the grain has 

 come to perfect maturity. We frequently see the effect 

 of the operation of the vital force of a tree, the growing 

 roots of which will lift heavy flag-stones of the side- 

 walk several inches above their level position ; and 

 roots of trees growing near dwelling-houses frequently 

 grow along the foundation wall and among the stones, 

 and damage the foundation of the dwelling to such an 

 extent, that repairs are required. 



In the production of every plant, from the most deli- 

 cate spear of grass to the towering oaks and rocking 

 pines of the forest, there is a wonderful effort of nature 

 to achieve a given result. The numerous fine rootlet? 



