84 Common Science 



flies open, his arms fly out, and every one thinks he is 

 bored to death. 



You might touch the clay that a sculptor is mold- 

 ing and make it elastic. The sculptor can mold all he 

 pleases, but the clay is like rubber and always returns 

 at once to its original shape. 



If you make a tree elastic when a man is chopping it 

 down, his ax bounces back from the tree with such force 

 as nearly to knock him over, and no amount of chopping 

 makes so much as a lasting dent in the tree. 



Suppose you step in some mud. The mud does not 

 stick to your shoes. It bends down under your weight, 

 but springs back to form again as soon as your weight 

 is removed. 



And if you try to spread some elastic butter on bread, 

 nothing will make the butter stay spread. The instant 

 you remove your knife, the butter rolls up again into 

 the same kind of lump it was in before. 



As for chewing your bread, you might as well try to 

 chew a rubber band. You force your jaws open, and 

 they snap back on the bread all right ; then they spring 

 open again, and snap back and keep this up automatically 

 until you make them stop. But for all this vigorous 

 chewing your bread looks as if it had never been touched 

 by a tooth. 



Sewing is about as difficult. The thread springs into 

 a coil in the shape of the spool. No hem stays turned ; 

 the cloth you try to sew springs into its original folds 

 in a most exasperating manner. 



On the whole, a perfectly elastic world would be a 

 hopeless one to live in. 



