244 



INDUSTRIAL PLANTS 



stiffness through considerable length together with lightness 

 are most important. 



Vehicles, in their running parts, require great toughness 

 together with elasticity in order to meet the very severe 

 and frequent shocks and wrenchings to which they are sub- 

 jected; while on the body lightness and stiffness are especially 

 desirable. 



Fig. 228, II. — Willow. A, pistillate flower-cluster. B, stainiiiate fiov.-pr, 

 enlarged. C, same, cut vertically. D, pistillate flower, enlarged. 

 E, pistil, cut vertically. F, seed, entire. G, same, cut vertically. 

 (Baillon.) 



Harness though made mostly of other material may con- 

 sist largely or wholly of wood, as with certain saddles, stirrups,, 

 hames, and yokes; and then, as being subject to much the 

 same strains as parts of vehicles, needs scarcely less stiffness, 

 lightness, and elasticity than they. 



Road materials, including wooden pavements and railway 

 ties, require blocks or logs of exceptional strength and dura- 



