NATURAL PLAY. 149 



already mentioned that all of what we call " the 

 principles of things," admit of a certain play, or 

 have as it were an extent to which they can be 

 bent or driven, and yet recover themselves, if 

 that which bended or drove them is withdrawn. 

 A bow is no bad illustration here; because the 

 elasticity of the bow is an instance of one of those 

 very powers. Now when the skilful archer bends 

 his bow it pulls the string to a perfectly straight 

 line ; then when he grasps the bow with his left 

 hand, sets the arrow upon the string, holds the 

 string on the fingers of his right hand like hooks, 

 that arm being doubled back into that position in 

 which it can bear the greatest strain without 

 moving, which is when the bent fingers are a very 

 little behind and under the right ear ; then, if he 

 stretches his left arm with proper skill and rapidity, 

 and so plunges the whole mass of his body and 

 the whole effect of its velocity into the bow, the 

 elasticity of the bow gives way, and "the cloth- 

 yard shaft " is drawn to the head. But if the 

 bow is " made of a trusty-tree" not a jot of its 

 elasticity is destroyed, but the more vigorously it 

 is drawn the more it accumulates ; and if the bow- 

 man slips his fingers at the very instant of his 

 utmost stretch, the returning bow sends the arrow 

 in perfect silence through the air fleeter than an 

 eagle. If, however, the bow were too small for the 

 man, he could draw it either till it broke, or till its 

 substance were so much injured that it would not 

 spring ; and if it were made of brittle wood, or of a 

 pliant osier twig, it might be overcome by the 

 strength of a child. 



It is the same with matter in resisting heat : 

 in some kinds of matter there is much resistance, 

 o 3 



