40 HOLLOW STEMS. 



MOTHER. 



I am not surprised at your question : The 

 reason is, that the same quantity of matter acquires 

 much greater strength, by being disposed in the 

 form of a hollow cylinder, than if it were compressed 

 into a solid one, which would be much thinner. 

 The woody part of the smaller roots of trees is 

 generally in the centre, which makes them pliable ; 

 while in the trunk the wood is at some distance 

 from the centre, and thus gives great strength to 

 the stem, and is favourable to its upright growth. 

 We see other instances of the same structure in 

 bones, and in the feathers of birds; the strongest 

 bones, as those of the legs of most animals, being 

 hollow : and the hollow quills which are exceed- 

 ingly light, that the bird may fly the better are 

 wonderfully strong, and much less apt to bend, 

 than if their substance were contracted into a solid 

 cylinder. 



When the joints of the bamboo are bored 

 through, they serve for water-pipes ; and walking- 

 sticks and fishing-rods are made of the smaller 

 stalks. 



EDWARD. 



Are not the chairs in your room made in imi- 

 tation of bamboo ? 



MOTHER. 



The frames are but the seats are made of 

 Bull-rushes, Scir-pus lacus'tris, a plant also of the 



