SUPERSTRUCTURES. 561 



10 to 20 feet long, and 5| inches to 1 foot broad, the usual 

 breadth being 8 inches to 1J feet. They are used for floors, 

 door-panels, cabinet-making, etc. 



iii. Battens, or small boards, may be 8 feet to 20 feet long, 

 and in section 4 inches by f-inch, up to 7 inches by 3 inches. 

 They are used for door- and window-frames, etc. 



4. Cloven Timber. 



Cloven timber comprises all those sorts of timber in which 

 the wood is split, or cloven, along the direction of the fibres ; 

 it comprises staves for casks, park-palings, laths, shingles for 

 roofing, spokes for wheels, rungs for ladders, hurdle- wood, etc. 

 This class of wood is characterised by the fact, that the fibres 

 not being severed, the wood preserves its natural elasticity 

 and strength and is much less permeable by liquids ; it is less 

 liable to warp and crack than sawn timber. The work of 

 cleaving timber is also more expeditious and requires simpler 

 implements than sawing, and there is scarcely any waste of 

 material involved. In cleaving wood it is advisable, when- 

 ever possible, to work from the centre of the piece of wood 

 outwards. 



SECTION II. TIMBER USED IN SUPERSTRUCTURES.* 



(a) Different Kinds of Superstructure. The term super- 

 structure includes all parts of buildings that are above 

 ground or water, so that the timber used in their construc- 

 tion may be exposed to the external air and to atmospheric 

 influences, but not to moisture from the soil or in water- 

 courses. Building- timber may be distinguished as sawn 

 timber (beams, planks and scantling), which is fitted by a 

 carpenter, and planed timber used for floors, doors and 

 windows, and fitted by a joiner. 



According to the demands on the durability, strength, 

 beauty, etc., of the timber used, and to its local value, 

 different modes of building are employed, some of which 

 use timber in large quantities, and others much more 

 sparingly. 



* M. I>i/.h;s. Haii'lbuch dor forstl. Baukmicie,'' Berlin, l.S'.'i'. 

 F.U. O 



