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WOOD TURPENTINE. 



This product when properly made and refined has a specific gravity 

 of from 0.860 to 0.880 at 20 C., though the first runnings from the 

 still may have a lower and the last runnings a higher specific gravity; 

 95 per cent should distil between 150 and 185 C. This turpentine 

 closely resembles spirits of turpentine from gum in most of its prop- 

 erties, and sells for from 2 to 10 cents less per gallon (depending on 

 the care with which it has been refined) than gum spirits, for which 

 it has been used as a substitute and adulterant. The processes of 

 production and the technical value of this material are now being 

 studied,, but as the work is not completed no conclusion as to the 

 relative value of wood turpentine as compared with gum spirits can 

 be given at present. 



A few words may be of interest, however, as to the best methods of 

 producing, refining, and marketing this article. When wood tur- 

 pentine was first placed upon the market it was very irregular in 

 composition, owing to the fact that but little was known of its nature 

 and producers were unacquainted with the proper methods of refin- 

 ing. As has been stated, turpentine as commercially produced is not 

 a definite compound, but a mixture of closely related terpenes, and 

 consequently it differs from moment to moment while distillation is 

 taking place and its distilling temperature rises, so that the turpen- 

 tine obtained at the close of a distillation is much heavier and differs 

 in many ways, particularly in odor and color, from the first runnings 

 from the still. This statement applies as well to gum spirits. The 

 distiller seldom realizes the importance of this fact as affecting the 

 uniformity of this product. In a few instances the gravity of the 

 distillate is taken as the turpentine passes from the condensers, and 

 if the hydrometer is carefully watched and the specific gravity is not 

 allowed to rise above 0.875, the resulting turpentine is fairly uniform 

 and satisfactory. As a rule, however, the close of the turpentine dis- 

 tillation is determined by the appearance of the oil, the formation of 

 beads or foam on the surface indicating that heavier oils are beginning 

 to distil. As this point is usually not carefully watched, the result 

 is that the product of a plant differs from day to day in color, odor, 

 and specific gravity, and its market value is lowered accordingly. 



Although considerable improvement has been made, wood tur- 

 pentine still varies greatly in composition, much to its detriment 

 commercially. That produced by steam distillation has, in well- 

 refined turpentines containing but a small amount of heavy oils, a 

 pleasant, fresh pine odor and but little color, while the heavier portions 

 of the steam-distilled oils have a more penetrating and lasting odor, 

 somewhat resembling that of camphor, and the more of these heavy 

 oils the turpentine contains the stronger its odor and the more it 



[Cir. 36] 





