CHAPTER XI 



THE LIBERATION OF ENERGY 



87. WE have already seen that energy is 

 liberated by the splitting up of complex 

 into simpler substances. By liberation we 

 mean the setting free of energy as kinetic 

 energy. Thus by the explosion of gunpowder 

 or of gun cotton, the mass is resolved into 

 gases at a high temperature, and the expansion 

 of these gases is used to drive a projectile 

 from a cannon. The energy of the explosive 

 is resolved into heat and motion. This latent 

 energy may be set free by communicating to 

 it the shock of a hair trigger, and the amount 

 of energy of the hair trigger is infinitesimally 

 small compared with that set free by the 

 explosion. The energy of the trigger may be 

 regarded as a liberator of the energy in the 

 explosive. This analogy helps in understand- 

 ing the phenomena in certain tissues. Thus 



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