MEN AND TREES 



no better world — that pain and struggle and dis- 

 appointment are necessary for his development, and 

 that to long for a state in which these things do not 

 exist is like the stream longing for a dead equilib- 

 rium. All power and all growth come from a break 

 in the repose of the physical forces. There is no 

 power in a uniform temperature, nor in water at a 

 dead level. Mechanical power comes down an in- 

 cline, vital power is a lift on an up-grade — all 

 growing things struggle upward; the vegetable and 

 animal world lift the earth elements up against 

 gravity into an unstable equilibrium. Mechanical 

 things run down the scale toward a stable equilib- 

 rium. 



Our life goes on by virtue of some principle or 

 force in matter that tends constantly to break up 

 the stable into the unstable, to force the elements 

 into new chemical combinations. Our machines 

 dissipate energy in doing work; the living body con- 

 serves energy in the same process. It grows strong 

 by the obstacles it overcomes, up to the limits of its 

 powers. The clock runs down, the energy we put 

 into it in winding it up is dissipated; but the growth 

 of a living body is a winding-up process, a dra wing- 

 in and a storing-up process. In the wood and coal we 

 burn is stored up the heat of the sun. In burning 

 them and driving machinery by means of the heat 

 developed, the energy is dissipated. In manual 

 labor the human body dissipates energy also, and 



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