244 



INDUSTRIAL PLANTS 



stiffness through consideral:)le 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. 



P '' II HI I 1(1/ 



r "III |« 



Fig. 22.S, II. — Willow. ,1, ].iolill;iti' flciwcr-clustcr. B, .xtaiiiinatc flnv,-i-r. 

 eiilargi'd. C', aanic, cut vertically. D, pistillate IIdwci-, enlarj^ed. 

 E, pistil, cut vertically. F, seed, entire. G, same, cut VL'rtieallj'. 

 (Baillou.) 



Harness though made mostly of other matcM-ial may con- 

 sist largely or whollj^ 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 stiffn(>ss, 

 lightness, and elasticity than llu'v. 



Road materials, including wooden pavements and railway 

 ties, refjuire blocks or logs of exceptional strength anil dura- 



