50 



WOOD TU&PENTIHES. 



the refined pine oil from A 2 . (See fig. 20.) The analyses of the 

 products obtained from one run, as shown in figures 45 and 46, give 

 a good idea of the separations obtained under these conditions. The 

 turpentine contained about 4 per cent pine oil, and the pine oil con- 

 tained about 2 per cent turpentine. 1 This seemed to be the most 

 complete separation possible, since with larger proportions of pine 

 oil in the turpentine the amount of turpentine in the pine oil de- 

 creased, and vice versa. 



Another interesting result was obtained in the test for determining 



the proper control of the distillation, 

 in which it was found that the control 

 of the still could be secured through 

 the specific gravity of the products 

 rather than through an arbitrary 

 speed. Where the specific gravities of 

 the two constituents to be separated 

 are different, the specific gravity gives 

 a nice control; but with a crude tur- 

 pentine, such as No. 3, where two 

 products (heads and hearts) have 

 nearly identical gravities this method 

 is not applicable. 



SUMMARY OF EXPERIMENTS. 



The crude turpentines that were ana- 

 lyzed are sharply divided into two 

 groups according to their compositions 

 and to the methods used in their pro- 

 duction. The means for their proper 

 refining naturally follow the same 



195 200 205 eiO 



P,o.46.-Bomng point and specific g rou P in & which is as f oll WS : 



gravity curves for pine oil ob- 



Group 1. Includes crude turpen- 



tained in commercial refining of t j Q 4 an d 5, which Were prO- 



crude turpentine No. 5. ^ 



duced at temperatures below 200 O. 



Group 2. Includes crude turpentines 1 and 3, which were pro- 

 duced at temperatures above 200 C. 



1 It will be noticed that figs. 45 and 46 are different in many ways from the pre- 

 ceding distillation curves. Index of refraction curves are not given, the boiling-point 

 values are uncorrected, and the percentages are by volume and not by weight. These 

 represent the results of analyses with portable apparatus, which can be set up and used 

 without the conveniences of the chemical laboratory. Two 50 c. c. cylinders, graduated 

 to 1 c. c., and one 500 c. c. measuring flask, take the place of the more delicate balances 

 in determining the percentages of distillate, and the refractometer and barometer can be 

 dispensed with ; otherwise the method is the same. For many purposes this method is 

 sufficient; but for close, careful work, the refinements described on pages 11-13 are 

 necessary. 



