SEASONING AND IMPEEGNATION OF TIMBER 275 
open air seasoning. One of the advantages of kihi 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. Kot 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 
T 2 
