58 



WOOD TURPENTINES. 



redistilled with steam in a small laboratory still without a fraction- 

 ating column ; the composition of the redistilled turpentine is shown 

 in figure 54. 



COMPOSITION OF HEAVY OILS IN WOOD TURPENTINES. 



The presence of considerable quantities of heavy oils in the crude 

 wood turpentines produced by steam distillation (see analyses of 

 crude turpentines Nos. 2 and 4, figs. 26 and 35) indicates that some 



160 165 170 175 180 185 190 195 

 O &<b &7 & A3 .90 9\ 3Z .93 

 9 L468 U7O \A7Z 1474. L476 L478 U80 



FIG. 51. Boiling point, specific 

 gravity, and index of refraction 

 curves for the turpentine obtained 

 from crude No. 4 analyzed after 

 three months. 



I6O 165 I7CP 175 ISO |65 190? 195" 

 O & 7 8 9 .91 S2 .95 34 

 9 1468 U10 1472 L4T4 1416 L478 1480 



FIG. 52. Boiling point, specific 

 gravity, and index of refraction 

 curves for the turpentine ob- 

 tained from crude No. 5 ana- 

 lyzed after six months. 



heavy oils, as such, are present in the wood itself, and are not formed 

 during the distillation process. Experiments on steam distillation of 

 longleaf pine have further confirmed these indications, since it was 

 found that the proportion of heavy oil in the crude turpentine did 

 not seem to be directly influenced by the temperatures of the dis- 

 tillation. 



In the usual commercial refining practice these heavy oils are dis- 

 tilled over after the turpentine, and are marketed without further 

 treatment as " pine oil." It was probably a sample of this pine oil 



