EXPERIMENTS IN REFINING WOOD TURPENTINE. 31 



fractive index, and behavior on redistillation are in general har- 

 .ony, as is to be expected. In general, the larger the percentage of 

 the crude turpentine contained in the first or A fraction and the 

 laller the percentage of turpentine in the distillate, the higher the 

 pecific gravity and the smaller the quantity passing over below 

 170 C. on redistillation. The figures also indicate that those frac- 

 tions of which fully 90 per cent passed over below 170 C. on redis- 

 illation constituted at least 54 per cent of the distillate from the 

 fining still. Those fractions which constituted from 54 to 30 per 

 ent of the distillate contained large quantities of heavy oils, and a 

 cond distillation was necessary to separate them and obtain a 

 roduct 90 per cent of which passes over below 170 C. 

 The data under barrels 7 to 11 A, 7 to 11 A + B, and 1 to 6 A (Tables 

 and 8) which were mixtures of first or A fractions, show that on a 

 cond distillation an entirely acceptable wood turpentine was 

 btained, and that approximately 92 per cent of the first fraction 

 as light oil. Approximately 50 to 54 per cent of the crude oil was 

 ecovered in the first distillation as a high-grade wood turpentine, 

 he highest figures, those on barrel 3, indicated that the crude tur- 

 ntine employed did not contain more than 60 per cent of oils 

 istilling below 170C, while those on barrel 4, which are considered 

 the most reliable, having been corrected for variations in pressure 

 and temperature, indicate 54 per cent of light oil distilling below this 

 temperature. This figure is probably correct within 2 per cent. 

 That is, the crude oil contained from 52 to 56 per cent of light oils 

 distilling below 170 C. The separation in a single distillation of a 



/90x54\ 

 uniform commercial fraction containing 90 per cent of these ( .QQ j 



or 48.6 per cent instead of 54 per cent, may be considered a satis- 

 factory separation, as it leaves in the heavy or pine oils 5 per cent of 

 the original light oils. This is, as will be seen by consulting the 

 tables, concentrated in a middle fraction constituting from 15 to 30 

 per cent of the original crude oil. Of this middle fraction 16 to 33 

 per cent is light oil, which can be almost completely separated by a 

 second distillation with steam in a column still. This second separation 

 will probably be sharper than the first, for the reason that by far the 

 greater part of the heavy oils present in the crude oil has been 

 removed, and of course the distillation is no longer affected by them. 



USE OF THE POT STILL. 



Similar, but less complete, experiments were conducted in Georgia 

 using an ordinary gooseneck turpentine still for refining crude steam- 

 distilled wood turpentine. These stills were charged with between 

 350 and 400 gallons of crude oils and refined with a slow current 

 of live steam, from 10 to 12 hours being required to distill off the 



