DISTILLATION OF STUMPWOOD. 65 



not as yet been placed on a satisfactory basis. The problem is ren- 

 dered more difficult because of the tendency exhibited by the ter- 

 penes as a class to pass readily from one form to another, and, in 

 addition, to combine with oxygen and the elements of water, under 

 conditions not well understood, to form a series of altogether more 

 complex, oxygenated bodies possessing properties entirely different 

 from those of the parent substance. 



Hesitation is felt, therefore, in assigning numerical relations to 

 or making an apportionment of the constituents that appear to enter 

 into the composition of this turpentine further than to say that it 

 seems to be largely made up of beta-pinene and dipentene, or its 

 optically active modification, d-limonene, a small proportion, 5 per 

 cent or less, of alpha-pinene containing perhaps some camphene, 

 and about 15 or 20 per cent of relatively high-boiling terpene de- 

 rivatives of unknown composition. The boiling-point and specific- 

 gravity curves indicate that the proportion of dipentene, or limonene, 

 probably exceeds that of beta-pinene. 



To what extent ordinary turpentine possesses "drying" power, in 

 the sense of being an oxygen carrier, is an open question in the 

 chemistry of paints and varnishes, and the relative oxygen-trans- 

 ferring power of beta-pinene compared to that of alpha-pinene has 

 not been determined. Kremers (5) found that limonene absorbs 

 oxygen quite as rapidly as does pinene, from which it may be in- 

 ferred that dipentene possesses this property to a like degree. 



To what extent the relatively high distilling temperature of tur- 

 pentine from western yellow pine will influence its value for use 

 in paints, varnishes, etc., can be definitely determined only from 

 actual use. The results obtained in comparative evaporation tests, 

 at room temperature, of gum spirits and wood turpentine from the 

 South, and wood turpentine from western yellow pine, secured in 

 the course of this work, however, show that the product from the 

 western yellow pine is materially slower in evaporating than either 

 the gum or wood spirits from the South. Moreover, the film re- 

 maining from the evaporation of the western yellow-pine wood 

 turpentine after drying twice as long as that from either of the 

 others could not, properly speaking, be said to have become dry or 

 resinified, compared with the films from the other samples. This 

 fact is undoubtedly due to the high-boiling constituents, the approxi- 

 mately 20 per cent which distils above 175 C. If this material 

 were not mixed with the turpentine where it does not belong, but 

 were added to the pine oil which it actually is, the turpentine would 

 dry much more rapidly and be more acceptable as a paint and var- 

 nish thinner. For some purposes, however, a slow-drying solvent is 

 desired, in which case the presence of the high-boiling constituent is 

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