iq 07] Herty — The Pine and its Products. 
35 
else for the preservation of our pine forests. Still again — 
what is the chemistry of “scrape” formation ? Why the va- 
riation in the amount of scrape formed in pines of different 
species and even among those of the same species ? These 
are a few of the many problems in this untouched field 
awaiting the skill and patience of the investigator. 
< 
DISTILLATION. 
Crude turpentine is of very little commercial use. It must 
be separated by distillation into its constituents, spirits of 
turpentine and rosin. In this country distillation is carried 
out in large copper stills heated by direct fire. During distil- 
lation a current of warm water is let into the still. The steam 
produced by the water added during distillation materially 
lowers the temperature and lessons the time necessary for the 
complete removal of the spirits of turpentine. An interesting 
study of this subject from a physico-chemical standpoint has 
been made by Prof. Vezes, of Bordeaux. By distilling at this 
lower temperature the possibility of destructive distillation of 
the rosin is avoided. The vaporized spirits of turpentine and 
the steam are condensed in a water jacketed copper coil and 
collected in a suitable vessel where separation takes place 
owing to the difference in specific gravities and the mutual 
insolubility of the two liquids. On completion of the distil- 
lation the cap of the still is removed and the excess of water 
boiled off to prevent opaqueness in the rosin. The molten 
rosin is then run through an opening near the bottom of the 
still into strainers lined with cotton batting through which 
it filters into a vat. After partial cooling the rosin is dipped 
into barrels where it slowly solidifies. 
During the summer of 1903 I had opportunity to study the 
systems of distillation practiced in France. Three types were 
found, first distillation by free flame and addition of water, 
as in this country, second by steam alone in steam jacketed 
stills, and third by a system of “mixed injection,” i. e. free 
