GENERAL PROPERTIES. 9 



Forest, Colorado, and the analyses made on this species are included. 

 A brief description of the samples upon which the analyses reported 

 in this bulletin were made is here given. 



Western yellow pine. The oleoresin which was obtained from the 

 Sierra National Forest was secured from trees tapped September 13 

 to October 12, 1910, which grew at an altitude of 4,000 feet. The 

 sample amounted to about 50 pounds. The oleoresin of this species 

 (var. P. ponderosa scopulorum Engelm.) sent from the Coconino 

 National Forest in Arizona was obtained from trees tapped August 

 1 to September 15, 1910. Two dippings were made at intervals of 

 three weeks. About 80 pounds of oleoresin, representing a mixture 

 of both dippings, were shipped. The trees tapped grew at an alti- 

 tude of 7,300 feet. 



Digger pine. The oleoresin was secured from trees which grew at 

 an altitude of 2,700 feet and were first tapped August 19, 1910. The 

 material shipped amounted to about 50 pounds. 



Sugar pine. The sample was from trees which grew at an altitude 

 of 5,800 feet; they were tapped from September 13 to October 12, 

 1910. The sample weighed about 5 pounds. 



Lodgepole pine. The trees, at an altitude of 6,000 feet, were tapped 

 from September 13 to October 12, 1910, and the sample weighed 

 about 5 pounds. 



Pinon pine. The oleoresin was secured from trees tapped from 

 June 9 to October 31, 1911. The sample, amounting to 50 pounds, 

 represented the "dip" secured from 5 dippings at 3-weeks intervals. 



In "all cases the oleoresins were collected by a cup system. The 

 samples were shipped in closed tin cans within from 1 to 4 weeks 

 after collection. A further period, varying from 1 to 2J months, 

 elapsed before the examination of the samples was begun, during 

 which time the material was retained in the shipping cans. The 

 metal of the cans showed no indications of attack by the crude gum. 



METHODS OF EXAMINATION. 

 OLEORESIN. 



The general examination of all the oleoresins was the same. From 

 350 to 400 grams of the crude resin were distilled with steam in a 

 tared 1.5-liter balloon flask, with a* Kjeldahl connecting bulb tube 

 placed between the flask and condenser to prevent any rosin from 

 being carried over mechanically. The rosin remaining in the flask 

 was kept heated until all the water had been expelled, care being 

 taken that the temperature did not exceed 145. When bubbles 

 ceased to form on the surface of the rosin, on agitation, the removal 

 of the water was considered complete. The rosin was then strained 

 through two layers of fine muslin, and that which adhered was com- 

 58237 Bull. 11913 2 



