PLIABILITY. 45 



of softwoods us ojiposed to hardwoods. This is chiefij' owing to 

 the length and straightuess of their fibres, and to the large 

 lumina of their cells and fibres which give more play for bending 

 than in hard woods. Hence, root-wood is more flexible than 

 stem-wood, and the latter more flexible than brittle branch-wood, 

 except in the case of the flexible branches of birch, spruce, and 

 some other species. 



The age of the wood also has an influence on its flexibility, as 

 young wood, and especially sapwood, is in many species more 

 flexible than old wood, the heartwood of many old trees having 

 very little flexibility. Wet soil in the case of oaks, beech, and 

 other species produces brittle wood. Resin increases the 

 flexibility of woods. 



The most flexible woods are the young stool-shoots of willows, 

 birch, hornbeam, aspen, ash, oaks, elms, &c., and branches of 

 birch and spruce ; young roots of Scotch pine and also of spruce, 

 grown in poor, sandy soil, where they attain a considerable 

 length, possess great flexibility. The following woods are con- 

 sidered naturally flexible : birch, mountain-ash, willows, poplars, 

 cork-elm, hickory, species of Sorhus, saplings of oak, hazel, and 

 suppressed spruce, &c. 



Flexibility is a necessary quality for wood in many industries, 

 such as for sieve- and drum-frames, staves, hoops for casks, 

 basket-work and withes for binding faggots or rafts of floating 

 wood ; the cartwright also requires long-fibred, flexible wood for 

 shafts. 



Steaming is largely applied to wood by shipbuilders in casing 

 the curved parts of ships, when steamed planks are nailed on 

 damp and hot. Similarly, curved planks are used in carriage 

 building. 



Bent-wood furniture is also made from steamed or boiled 

 beech wood, and steamed split pieces of ash and oak are 

 twisted round cylinders into spiral- shaped banisters for stair- 

 cases. The curved pieces of wood in violins and other stringed 

 instruments are all steamed. These industries show what a large 

 amount of pliability even hardwoods may possess when steamed. 



Withes are softened in the fire, or even in ovens used for the 

 purpose, before being twisted. 



Wood which has been steamed and bent retains its new shape 

 permanently when thoroughly dry. This may be seen in the 



