of liquor allowed about 1,000 c.c. free space in the 

 dome of the digester for steam collection. This 

 was found to be insufficient, due to surging over 

 of the alkaline liquor. Contamination of the tur- 

 pentine distillate by alkali and rosin soap not only 

 resulted in a loss of rosin but also caused more or 

 less retention of 'turpentine in the aqueous layer. 

 The chips were heated with a 3.4 per cent NaOH 

 solution (2.6 per cent Na 2 O), the total caustic 

 being 3.2 times the amount theoretically necessary 

 for the saponification of the rosin. A steam pres- 

 sure of 20 pounds was maintained for 3.5 hours. 

 Although the bulk of the turpentine was removed 

 in the first hour, the fullness of the digester pre- 

 vented efficient recovery of the least portions in 

 the time allowed. On examination of the chips 

 it was found that considerable rosin still remained 

 unsaponified. In the soda cook a 4.1 per cent 

 NaOH solution was used, providing a ratio of 

 Na 2 O to wood of 24 per cent. A pressure of 100 

 pounds for 2| hours failed to give proper dis- 

 integration ofthe wood fibre. 



In Experiment 2 the digester was filled only 

 about two-thirds full and a very small excess of 

 caustic soda (1.6 times theory) was used. Dis- 

 tillation was carried on at 30-40 pounds in an 

 attempt to hasten the evolution of the turpentine. 

 After two hours the fractions became very small 

 and steaming was discontinued at the end of 

 3 hours. Conditions for turpentine evolution were 

 particularly favorable on account of the large free 

 space left in the digester and there was no con- 

 tamination of the distillate. However, the yield 

 of crude turpentine (41.3 gals, per cord) was lower 

 than in subsequent runs and a large proportion of 

 the rosin was left in the chips in the free state. 

 Titration of the liquors showed that the caustic 

 had been completely neutralized during the prelimin- 

 ary extraction, which explained the imperfect pene- 

 tration of the wood. This pointed to the necessity 

 of employing a larger excess of alkali in order to 

 take care of neutralization by the humic acids 

 formed. The soda cook was carried on with 2.6 

 per cent caustic solution. The maintenance of 



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