more extended decomposition of lignocellulose. The 

 extracts were much darker on this account. 



2. Heating Under Pressure. 



For the preliminary experiments at elevated 

 temperatures a small autoclave of about 1500 cc. 

 capacity was used. The autoclave was fitted with 

 a pressure gage, thermometer pocket and relief line 

 leading to a condenser. 



With shavings the evolution of turpentine com- 

 menced as soon as pressure was evidenced and the 

 main bulk of the volatile oils distilled over with a 

 low ratio of water vapor in a very few minutes. 

 In about half an hour the yield of turpentine 

 amounted to approximately 35 gallons per cord. 

 Later experiments showed that the true turpentine 

 content of the wood was about 45 gallons per 

 cord. Frothing was excessive, especially during 

 rapid evolution of the turpentine and care was 

 necessary in controlling the relief line. Extraction 

 of rosin was rapid and the extracts were notice- 

 ably darker than those obtained below 100. The 

 caramel odor detected in all the alkaline extracts 

 was more pronounced in this case. 



3. Vacuum Treatment 



The apparatus used consisted of a hemispherical 

 porcelain bowl of about 4 liters capacity, set in a 

 water bath and surmounted by a convex glass 

 cover resting on a rubber gasket. A thermometer 

 was inserted in the top and the delivery tube was 

 connected to a condenser and receiving flask, the 

 side tube of the latter being attached to a mano- 

 meter and suction pump. 



500 grams of thin chips were treated with 2500 

 cc. of 2.4 per cent NaOH solution, calculated to 

 supply 3 times the amount of alkali necessary for 

 saponification. The water bath and suction pump 

 were first adjusted to carry on distillation at a 

 high vacuum 20-25 inches so that the tempera- 

 ture could be held below 70C. The action of the 

 caustic was not very rapid. 



Frothing was excessive while turpentine was 

 being evolved and constant attention was necessary 



22 



