COATINGS FOR WOOD. 179 
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 con- 
sistency. Covering with cloth or tarred paper also lessens check- 
ing. 
Good Coatings for Wood consist of oily or resinous 
substances that are easily applied in a smooth coat and dry 
readily, yet do not have any tendency to crack or peel off. They 
should be applied to the whole exposed surface. 
Coal Tar is one of the best materials for covering wood to 
increase its durability. It is best applied hot, especially if mixed 
with oil of turpentine, as it then penetrates more deeply. A 
mixture of three parts coal tar and- one part unsalted grease, to 
prevent the tar from drying too quickly so it may penetrate the 
wood better, is recommended. One barrel of coal tar will cover’ 
irom two to three hundred posts if it is properly applied. 
Oil Paints are next in value. Boiled linseed oil is used 
with lead, pulverized charcoal, or other similar material, to give 
it substance. Soaking the dry wood in crude petroleum is also 
recommended. 
Lime Whitewash is a good preventive of decay in wood 
and, although not as good for this purpose as coal tar, it is very 
desirable. As with all other preservatives that are applied to the 
surface, the wood should be very dry before it is applied, and 
the wash should be applied evenly over all the exposed parts. It 
is on account of the lime that washes out of the mortar that the 
shingles on a roof just below the chimney last longer than on 
other parts of the roof. But if whitewash is to be applied to 
shingles it should be applied before they are laid by dipping. 
Charring those parts of posts or timbers which come in 
contact with the ground is a good preventive, provided a thick 
layer of charcoal is formed and the work so carefully done as not 
to cause the timber to crack, since deep cracking exposes the 
interior to decay. If not carefully done the timber may be 
seriously weakened. 
