DURABILITY OF WOOD. 73 



in an unimpaired state of preservation in some of our very 

 oldest building's. 



Curing is one of the most important processes in its effect 

 on the. durability of wood. Well cured wood resists decay far 

 better than fresh wood, because it contains an insufficient 

 amount of water for the growth of fungi. Green wood covered 

 with paint before it is dry is often destroyed by dry rot, since 

 this fungus finds abundant moisture under the paint and the 

 protection which was intended for the wood really protects its 

 enemy, the fungus. Paint and other wood-protecting com- 

 pounds are efficient only when they are applied to dry material, 

 which they preserve by protecting them from moisture. But 

 fence posts or other timber to be used in moist places, if well 

 cured, will even if not protected, last much longer than fresh 

 cut timber. The amount of moisture in wood, then, is the 

 most important factor in influencing its durability. 



Timber is Best Cured Under Cover, where it is protected from 

 the sun and the full force of the wind but has a good circula- 

 tion of air. If piled in the open, it is a good plan to sbade 

 it. When piling green or wet dmber, place lath or other 

 strips of wood of uniform size under each log. post or tie. In 

 piling sawed lumber the -lath should be placed at the ends, as 

 in this position they in a measure prevent checking on the 

 ends. 



From twelve to eighteen months is generally sufficient to 

 cure wood for ordinary use, while Tor special work ten or 

 more years may occasionally be required. If green or wet 

 timber is closely piled in warm weather it is likely to rot. 

 The best method of curing timber without resorting to the use 

 of expensive apparatus is to work it up at once and soak it in 

 water for from one to three weeks to remove the sap from the 

 outside of the wood. It will then season more quickly and be 

 more durable than when dried without soaking. Sometimes 

 it is absolutely necessary to thus water season large timbers 

 as it is impossible to get the sap out of them by atmospheric 

 seasoning. Large checks or cracks in the ends of logs or 

 other timber of large dimension may be avoided or greatly 

 lessened by painting the ends with linseed oil mixed with 

 ground charcoal or other material to give it consistency. 

 Covering with cloth or tarred paper also lessens checking. 



