64 
BULLETIN 1036, U. S. DEPARTMENT OF AGRICULTURE. 
Recently Bateman and Town (26) have shown that the loss of 
creosote by weight because of evaporation in laboratory open-tank 
treatments is in direct proportion to the area of the surface of the 
oil, and is also dependent upon the volatility of the creosote. They 
give the equation log L = 0.0165 V— 0.347 as the daily loss per square 
foot of exposed surface, when the temperature of the bath is 195° 
F. In this equation log L is the logarithm of the loss and V is the 
percentage of creosote distilling below 270° C. The constants 0.0165 
and 0.347 will vary if any of the conditions are used except those 
under which the experiment was carried out. Figure 32 gives a 
curve of the above equation, with the experimental data plotted 
upon it. 
I" 
I 
I 
/ Z 3 4 S 6 7 3 9/0 
A OSS " f^oc /7cKs /oer Sfuore foot />es day 
Fig. 32. — Relation between the volatility and the loss by evaporation of 
creosotes from open tanks. 
Calculations show that it is very likely there is a mathematical 
relation between the rate of loss of creosote from treated wood and 
the amount and character of the creosote injected. The general 
form of the equation, as obtained from preliminary calculations, is 
KAHl-Y) s Y 2 
^O 
o 
1<r 
/ 
/o 
/ 
) 
/ 
1 
J> 
B-Y 
=X 
where K is a constant for the location, A is the weight of creosote 
injected per cubic foot of wood, B the percentage of creosote dis- 
tilling below 270° C, Y the loss by evaporation, and X the time 
required. 
Figure 33 gives two curves in which the above equation has been 
used on two different creosoted sticks which had different grades of 
creosotes and different absorptions per cubic foot. In one curve the 
amount of oil distilling below 270° C. was 92 per cent, in the other 
curve 49 per cent. The amounts of oil injected per cubic foot were 
