The Oleoresin varies widely in amount but its 

 composition is fairly uniform, the volatile oils 

 comprising approximately 20 per cent of the crude 

 gum, and colophony or rosin making up the remain- 

 ing 80 per cent. The volatile oils or " crude turps" 

 yield from 60 to 80 per cent of actual turpentine 

 and from 40 to 20 per cent of heavier oils, known 

 collectively as "pine oil." As it exists in the wood, 

 the turpentine consists mainly of terpenes of the 

 formula C TO H T6 , chiefly a-pinene with smaller 

 amounts of b-pinene, dipentene, camphene, and 

 traces of other oils. (U. S. Dept. Agric., Forest 

 Service, Bull. 119, p. 7; Bur. Chem. Bull. 144, 

 p. 21). The turpentine fraction distils between 

 155 and l80C., the main portion passing over 

 close to the boiling point of pinene (155-156C.). 

 The pine oil consists essentially of terpineol, with 

 small amounts of borneol, fenchyl alcohol, limonene, 

 cineol and other terpenes and related compounds. 

 Gum turpentine issues from the sapwood of the 

 living tree and consists almost entirely of pinene, 

 whereas the volatile oils of the heartwood contain 

 appreciable amounts of dipentene and heavier oils. 



The colophony or rosin consists chiefly of mono- 

 basic rosin acids. The main constituent (80-90 

 per cent) is believed to be abietic acid or its an- 

 hydride. Authorities differ as to the exact com- 

 position of abietic acid, some holding to the for- 

 mula C 2 oH3o0 2 and others to C^H^C^ (see Forest 

 Service, Bull. 119, pp. 7-8 for references). There 

 are no esters, but bodies of a lactone nature are 

 present in small quantity as shown by the dis- 

 crepancy between the saponification and acid 

 numbers. 



The true wood, (Klason, see Schwalbe, " Die 

 Chemie der Cellulose," pp. 395 and 441; Dean 

 and Tower, J. Am. Chem. Soc., 29, (1907), p. 

 1119) considered apart from oleoresin and mois- 

 ture, is essentially lignocellulose, made up of 55-65 

 per cent of stable cellulose, (C 6 HIO 0$ )n, associa- 

 ted in a colloidal state with about 30 per cent 

 of lignin, a carbohydrate of uncertain composi- 

 tion and higher carbon content, approaching the 

 empirical formula C 6 H 7 O 3 (Cross and Bevan 



6 



