“WOOD IN GENERAL _ 245 
bility to stand satisfactorily the heavy loads and the alter- 
nate drying and wetting to which they are subjected. 
Fences require wood as durable under similar exposure 
but without the same mechanical strain. 
Poles, as for flags and wires, need similarly to resist decay 
and also to meet about the same requirements as spars. 
Trestlework, as for bridges and the like, needs especially 
stiffness with durability under exposure to weather. 
Piling, as the foundation for bridges, wharfs, and so forth, 
needs not only to be stiff but to be durable under water or in 
contact with moist soil. 
Mine timbering must be equally strong and at the same 
time able to resist decay under conditions of dampness much 
more trying than those of entire submergence. 
_ Industrial implements, machines, and weapons, mostly 
require wood of especial toughness to serve for handles, cogs, 
spindles, gunstocks, and the like. 
Canes and umbrellas call for fancy woods of attractive 
appearance and considerable stiffness, small dimensions 
being no drawback. 
Surgical appliances such as splints, crutches, and artificial 
limbs are best made of wood that is both stiff and light. 
Recreational appliances such as tennis-rackets, base-ball 
or cricket-bats, hockey-sticks, golf-clubs, croquet-mallets and 
balls, nine-pins, balls and bowling alleys, billiard cues, check- 
ers, and chessmen, are made mostly of wood that is especially 
tough or hard. 
Musical instruments such as violins, guitars, and pianos 
depend for their quality of tone mainly upon the resonance 
of the wood used in their construction. 
Toys are made generally of woods which are most easy to 
work, and the same consideration largely influences the 
selection of woods for various minor articles such as spools, 
button-molds, shoe-pegs, toothpicks, and matches. Other 
uses of wood apart from its value as constructive material 
will be referred to later. 
To the plant which produces a as to us who use it, wood 
serves mainly for mechanical support. In large trees the 
trunk must be a column of great strength in order to hold up 
