82 OF WOOD IN GENERAL. 



out work roughly and let it season a little longer before 

 finishing. 



The strength of many woods is nearly doubled by seasoning, 

 hence it is very thriftless to use it in a green state ; as it is then 

 not only weaker, but is liable to continual change of bulk and 

 form. The longitudinal fibres of the wood being, as it were, 

 bound together by the radiating pith-rays, as the wood shrinks it 

 finds relief by splitting radially from the centre along the pith- 

 rays. When a log is sawn into four quarters, by passing the saw 

 twice through the centre at right angles, the outer annual rings 

 shrink the most, so that the two flat surfaces of each quarter of 

 the log cease to be strictly at right angles to one another. In 

 tangent-sawn timber, however, the same shrinkage causes the 

 centre plank to contract in thickness at its edge, whilst planks 

 cut from the outside will shrink in breadth, their edges curving 

 away from the centre of the tree. 



It seems to be generally agreed that natural or air seasoning 

 gives the best results. Firewood should be dried rapidly ; but in 

 other cases slow drying in cool air a process difficult to effect in 

 the tropics is most desirable in order to reduce the amount of 

 cracking. The timber should be squared as soon as cut, and even 

 halved or quartered, for the rate of drying depends largely on the 

 shape and size of the piece, an inch board drying more than four 

 times as fast as a 4-irich plank, and more than twenty times as fast 

 as a 10-inch timber. The wood is then piled in the seasoning 

 yard so as to be protected as far as possible from the sun and 

 rain, but with air circulating freely on all sides of each log. Bad 

 ventilation is sure to cause rot ; but at the same time exposure to 

 high wind is likely to cause unequal drying, and is, therefore, to 

 be avoided. One of the most fertile causes of decay is the leaving 

 of logs to sink into soft ground where they are felled, often in the 

 immediate neighbourhood of rotting stumps or dead twigs, the 

 most fertile source of infection by fungus-spores than can be 

 imagined. Timber should therefore be stacked, or at least 

 skidded a foot off the ground, as soon as possible and protected 

 by a roof. Experience is against the stacking of timber vertically 



