SEASONING AND IMPREGNATION OF TIMBER 275 



open air seasoning. One of the advantages of kiln drying 

 is that all parts outside as well as inside are equally dried, 

 and it allows of the timber being quickly brought into use, 

 but there is a risk of unequal shrinking or splitting 

 unless care is taken during the process ; kiln drying is 

 seldom used for large-sized timber. The time occupied in 

 kiln drying, as in the open air, depends upon the thickness 

 of timber under treatment, and it will take much longer, 

 longer even than in proportion to size, to dry baulk timber 

 than it will to dry planks ; as much as twenty times as long 

 is required to dry a 10-inch log as in the case of a plank 

 one inch thick. 



Charring the ends of wood and sometimes all over has 

 been tried at various times with a view to preservation, but 

 after the experience of many experiments it is questionable 

 if it is worth the cost. It is not uncommon to char the 

 ends of fence posts before they are put into the ground, and 

 this is required in the specifications of at least one county 

 authority in Great Britain for oak and other posts for 

 handrails on bridge approaches. 



Impregnation of Timber. The prevention of the propaga- 

 tion of fungi can generally be attained by a proper system 

 of seasoning when required for building work, but where 

 timber has to be placed in situations more conducive to the 

 production of fungus life, say in the ground as railway 

 sleepers or where it is liable to attack by the sea worm, it 

 is necessary to have, recourse to antiseptics of one kind or 

 another. 



Methods and processes for the preservation of timber are 

 as old as history. Rot and decay of timber were the bane 

 of the architect and engineer 2,000 years ago as they are 

 to-day. The famous wooden statue of Diana of the 

 Ephesians was kept saturated with oil of Nard by means of 



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