28 



WOOD TUKPENTINES. 



parison between the results obtained by the use of these two dephleg- 

 mators is shown in figure 14. The main difference between the curves 

 obtained by the two types of dephlegmators is in the specific gravity 

 in the vicinity of 90 per cent; the fractions obtained by distillation 

 through the Hempel column have a lower gravity over this part of 

 the curve, indicating a purer dipentene and therefore better frac- 

 tionation; the sharper break in the curves at about 80 per cent also 

 indicates better fractionation. On account of the simplicity and 

 cheapness of the Hempel column as well as its better fractionation, 

 it is recommended as the preferable dephlegmator for turpentine 



FIG. 15. Boiling cap section. 



distillations. This type of dephlegmator has been used in making 

 many of the distillations recorded in the following pages, and has 

 given very satisfactory results. 



KEFINING. 



Five samples of crude wood turpentine were refined; these were 

 collected from commercial plants using widely varying processes, a 

 brief description of which will be given. The apparatus used in 

 the refining and the method of conducting the distillations were 

 similar for all the samples. 



