OF FUNCTION ; OR, HOW WE ACT. 5 



Under certain conditions, it has an active power as 

 like that of the heart as could readily be devised, 

 What are those conditions ? They are very simple. 

 It must contain a spring in a state of tension : that 

 is, force must have been applied to it in such a way 

 as to store up power, by opposing the tendency 

 of the metal to straighten itself. Let us fix in our 

 minds this conception of a tension, or balancing of 

 two forces in the watch-spring. The power applied 

 in winding it up is exerted in opposing the elasticity 

 of the steel : it is compressed coerced. The pro- 

 duction of motion from it, when in this state, is a 

 quite simple mechanical problem : let it unbend, and 

 let wheels and levers be at hand to convey the force 

 where it may be desired. 



Let it be observed that the force thus exerted by 

 the spring, and on which the "functions" of the 

 watch depend, is truly the force that is applied by 

 the hand in winding it up. That force is retained 

 by the spring, as it were in a latent state, until it is 

 applied to use: it exists in the spring, as tension 

 a state intermediate between the motion of the hand 

 in bending it, and of the hands of the watch in their 



