62 



BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE. 



proportions as recovered from the crude turpentine, was carefully 

 distilled from a Hempel fractionating apparatus, and the boiling 

 point, specific gravity, and refractive index curves plotted from these 

 data. 



The boiling point, refractive index, and specific gravity curves 

 (figs. 6, 7, 8) point to the presence, to the extent of about 2 per cent, 



FIG. 6. Boiling point of distillate. 



of a body distilling at a relatively low temperature, having also a 

 much lower refractive index than the major portion of the distillate. 

 This is probably alpha-pinene, which in a pure state has a boiling 

 point of 155 C., a specific gravity of 0.858, and refractive index of 

 1.4660 at 20 C., whereas the corresponding values of beta-pinene 

 are 162 C., 0.868, and 1.4784. Polarimetrir readings on the first two 

 fractions, up to 6 per cent total distillate, showed laevo-rotations, in- 



