ANALYSIS, EEFINING, AND COMPOSITION. 



45 



odor of the first 10 per cent of the distillate was quite different from 

 the remainder. As in the case of crude turpentine No. 2, the amount 

 of this material is so small, and its properties are so slightly different 

 that it is unnecessary to attempt to separate it. 



HEARTS. 



The analysis of the hearts (fig. 37) showed about 6.5 per cent of 

 pine oil present as was to be expected from the manner of regulating 

 the distillation. 



i- 



LEGEND 



O 5P E-CIFI . 61 



165' 170' I75 180 185 I9O 195' 

 O K> JB7 8 9 30 .91 .93 -93 

 O 1468 WTO 1472 U74 1476 L418 L48O 



FIG. 37. Boiling point, specific 

 gravity, and index of refraction 

 curves for " hearts " obtained in 

 refining of crude turpentine 

 No. 4. 



205* Z\O ZI5 

 O .93 .94. .95 

 O 1.484. U86 1408 



FIG. 38. Boiling point, specific 

 gravity, and index of refraction 

 curves for " tails " obtained in 

 refining of crude turpentine No. 4. 



TAILS. 



The tails (fig. 38) were apparently entirely free from hearts ma- 

 terial, the very high values for the physical properties of the first 

 fraction, 6.5 per cent, indicating that only a very small proportion of 

 this fraction could possibly be made up of turpentine material. The 

 separation in this case is therefore very satisfactory, since the hearts 

 contain probably no more heavy material than is allowable in a good 

 grade of turpentine, and the tails are practically free from turpentine. 



PRODUCTS OBTAINED BY COMMERCIAL REFINING. 



In order to obtain a comparison between the efficiency (as regards 

 completeness of separation) of the column still, which was used in 



