1914 



Division of Forestry- 

 University of California 



EXAMINATION OF THE OLEORESINS OF SOME 

 WESTERN PINES. 



GENERAL PROPERTIES AND COMPOSITION OF OLEORESINS. 



A wound in the sap wood of a growing conifer induces, to a greater 

 or less extent, the flow of a liquid resembling honey in appearance 

 and consistency. This liquid, called oleoresin, consists of a solution 

 of resin acids in a volatile oil. 



Turpentine is the trade name applied to the volatile oil ; it is also 

 some tunes called "oil of turpentine" or "spirits of turpentine." In 

 Europe the term "oil of turpentine" is invariably used to denote the 

 volatile constituent, while "turpentine" alone signifies the oleoresin. 

 In this country the oleoresin is commercially known as "gum" or 

 "crude turpentine," while "dip" and "scrape" are terms commonly 

 used to signify, respectively, the portions dipped from the receptacles 

 used in turpentine operations or scraped from the scarified faces of 

 the trees. 



The turpentine, or volatile oil, is separated from the oleoresin by 

 distillation, and the residue in the still, after being freed from trash, 

 is the colophony or "rosin" of commerce. 



Turpentine, from the chemist's standpoint, consists of a mixture 

 of hydrocarbons having the empirical formula C 10 H 16 , called terpenes. 

 American turpentine consists largely of the terpene a-pinene, 

 with smaller amounts of /?-pinene l and camphene. 2 French tur- 

 pentine agrees closely with American turpentine in its physical and 

 chemical properties. 



Colophony or rosin is a hard, vitreous, amorphous body, breaking 

 with a conchoidal fracture and varying hi color from black to light 

 amber. It consists of monobasic resin acids, which usually can be 

 obtained in a crystalline state by appropriate treatment. 



Knowledge of the resin acids, their empirical formula, constitution, 

 and properties is in a very confused state. A large number of resin 

 acids have been described and held to be distinct bodies, but it seems 

 probable that the majority of these are modified forms of one or more 

 typical acids. American colophony is very generally considered to 

 contain from 80 to 95 per cent abietic acid. The physical properties 



i Schimmel & Co. Report, April, 1908, pp. 99-100. a Ibid., October, 1897, p. 68. 



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