108 Forest Club Annual 



when poles are removed hot from the oil, the outer coating of 

 oil which they carry on their surface, is drawn into the pole, 

 by the interior air contracting, before it reaches the ground from 

 the derrick. Borings in poles treated in this manner show that 

 the outer part of the wood is free from excess oil for a depth of 

 2 inches, while in the deeper part of the boring, creosote is found 

 free in considerable quantity. 



The third plan tried with a single tank system consisted in 

 heating the poles in hot creosote several hours allowing- the oil 

 to cool about 20, which required an hour and then removing 

 the poles from the partially cooled oil. The 20 fall in tempera- 

 ture draws in a small quantity of oil. The pole being now re- 

 moved and allowed to cool to air temperature the air contracting 

 in the wood draws the free oil in very deep, coating each pas- 

 sageway as it sinks in, until no free oil is left in the cells. This 

 secures the greatest protection for the smallest amount of creosote. 

 The treatment is very successful resulting in a penetration of 3 

 inches with five pounds of oil per cubic foot of wood. 



The preceding results were secured with a single bath treat- 

 ment. Much time can be saved with an equipment containing 

 two baths of the preservative, one hot and one cold. This may 

 be accomplished either by two tanks, or by an arrangement for 

 quickly changing the oil in the single tank. In this way the effect 

 of the previously described 18 hour treatment can be secured in 

 five hours or less. 



In the dry weather of summer, if the poles are thoroughly 

 seasoned, penetration of 2 to 3 inches with 6 pounds of oil per 

 cubic foot can be secured by heating the poles for one hour in 

 oil at 130 F. and then plunging them into air cold oil for from 2 

 to 5 minutes. The poles are removed very hot, the surface oil is 

 immediately drawn in and the poles are dry before they strike 

 the ground. 



The important conclusions to be drawn from the tank treat- 

 ing experiments with creosote upon Western Yellow Pine are : 



1. Poles should be well seasoned before treatment sea- 

 soned until they have lost 50 per cent of their green weight. 



2. Poles should be separated according to season of cutting 

 before treatment is possible. Summer-cut pine poles should not 

 be treated with other poles as they require a severer treatment. 



3. Very old poles should not be treated in the same run 

 with timber just seasoned. 



4. Seasoned pine can be very successfully treated with creo- 

 ?-ote with absorptions up to 15 pounds of oil per cubic foot of 

 treated timber and penetrations as deep as five inches. 



5. The desirable form of treatment is an empty cell treat- 



