(4) Any physical property, such as specific gravity or index of 

 refraction, may be used in the place of boiling temperature in these 

 curves; and the more physical properties determined, the greater 

 will be the reliability of the final interpretation. In the analyses 

 made by the Forest Service, the color, odor, and maximum boiling 

 temperature of all fractions were noticed, and specific gravity and 

 index of refraction were determined. 



THE NEW METHOD OF ANALYSIS. 



The complete method as finally modified consists, then, in distilling 

 the sample with steam through a dephlegmator and collecting the dis- 



FIG. 4. Apparatus used in turpentine analysis. 



tillate in several fractions. The color, odor, and boiling temperature 

 of each of these fractions are noted, and the weight, specific gravity, 

 and index of refraction of each determined. From these data, tables 

 are made and curves are plotted. The interpretation and comparison 

 of the curves furnish information concerning the composition of the 

 samples as shown by the physical properties of the leading constitu- 

 ents, and also render the similarity or dissimilarity of various oils 

 quickly evident. 



APPARATUS. 



The apparatus, shown in figure 4, is supported by the ordinary 

 laboratory stands and clamps, which are omitted in the drawing. A 



44780 Cir. 15208 2 



