30 



OLEOBESINS OF SOME WESTERN PINES. 



of concentrated hydrochloric acid were added, microscopic trian- 

 gular plates separated on cooling. These plates melted at 137 and 

 were completely liquid at 148. The activity of the resin acid was 

 determined in an alcoholic solution, the specific rotation, 

 52.77, being computed from the following values: 



a = -0.57 

 1= 1 



p= 1.33 

 (2 = 0.8122 



Analysis of the silver salt of the resin acid gave the following 

 results : 



Per cent. 

 0.1867 gram silver salt gave 0.0494 gram silver =26. 46 



Calculated for Ag^^HaA) =26.37 



CONCLUSIONS. 



From the distillation data it has been estimated that the volatile 

 oil from the oleoresin of Pinus edulis contains approximately 70 to 75 

 per cent or-pinene, about 5 per cent /?-pinene, and 15 to 20 per 

 cent <Z-cadinene. The oleoresin yields a resin acid of the formula 

 C 20 H 30 O 2 ; although no crystalline resin acid was obtained from the 

 colophony it may be assumed to consist of amorphous acids of the 

 preceding formula. 



SUMMARY. 



With the exception of the digger pine, the volatile oil from all the 

 species examined consists of terpenes (C 10 H 1C ), and sesquiterpenes 

 (C 15 H 24 ). The oil from the digger pine consists of the hydrocarbon 

 heptane (C 7 H 16 ), a normal constituent of petroleum. 



COMPARISONS WITH COMMERCIAL NAVAL STORES. 

 VOLATILE OIL. 



In Table 7 and in figures 1 to 4 the various oils examined are 

 compared with an average gum turpentine which consists of a mixture 

 of the volatile oils .of the Cuban pine (Pinus Tieterophylla Ell.) and 

 longleaf pine (Pinus palustris Mill.) : 



i 

 TABLE 7. Characteristics of the volatik oil from the oleoresin of various pines. 



first 80 per cent distills between 156 and 200 C. From Cuban and longleaf pines. 



