the end of the treatment to ensure evolution of 

 the last traces of turpentine. The ratios for this 

 period varied from 40 to 50. It will be apparent 

 that the ratios of condensed water vapor to tur- 

 pentine are well within the practical limits. In 

 fact, a much more rapid evolution of steam would 

 be justified in order to shorten the steaming 

 period. 



The nature of the turpentine curves suggests 

 that it might be found more economical in practice 

 to discontinue the preliminary steaming before the 

 last traces of turpentine were removed. This would 

 mean a saving in steam consumption and a less 

 severe attack of the wood itself. 



In conclusion it seems reasonable to assume that 

 a properly conducted alkali extraction will allow 

 recovery of all the volatile oils in the wood in a 

 high state of purity. 



Partial Fractionation of Volatile Oils 



Figure 3 will serve to show certain changes in 

 the nature of the volatile oils during the progress 

 of distillation. The fractions were saved separately 

 every fifteen minutes in Experiments 4 and 5 and 

 the refractive index and specific gravity constants 

 of each fraction were determined. The ordinates 

 have been chosen to represent the various stages 

 of turpentine distillation, expressed in per- 

 centages of the total turpentine content of the 

 wood. The backward turn at the end of each 

 curve is occasioned by the final fraction obtained 

 while drawing down the pressure. The average 

 constants, obtained by finally combining all the 

 fractions, are shown by the vertical lines. 



The curves of index of refraction and specific 

 gravity for a single experiment follow closely 

 parallel to one another. Moreover, the curves are 

 materially the same for the two experiments. It is 

 apparent that the oil became heavier as distillation 

 proceeded and that the last period of steaming 

 was spent in removing the fractions which approach 

 pine oil in general properties. This shows that 

 distillation of the crude turpentine is not coincident 

 with its liberation from the rosin, for otherwise the 



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