4 IG 



open vessels. After some days crystals were formed in some quantity with both 

 forms. These were rhombic crystals, and when purified by recrystallisation from 

 alcohol, melted at 116-117 C. with elimination of water. On melting these 

 terpin hydrates and taking the melting point of the terpins thus formed, it 

 was found that both melted at 102-103 C., and readily sublimed. The terpin 

 hydrate from either form was soluble in boiling water, in alcohol, and in 

 ether, and behaved chemically in exactly the same manner in every respect. 



A vapour density determination of the pinene gave almost the identical 

 figures required for the molecule C IO H l6 . 



The monohydrochloride was prepared with the dextropinene ; this had 

 the odour and appearance of ordinary camphor and melted at 123-124 C. 



Crystalline bromides were not obtained by ordinary methods. 



For the corresponding pinene from the oils of the closely-related genus 

 Angophora, see paper by one of us, Proc. Roy. Soc., N.S.W., August, 1913. 



The Eucalyptus Oils Yielding Pinene for 

 Turpentine Production. 



DURING the systematic investigation of the various Eucalyptus oils recorded in 

 this work, it was found that pinene is a most pronounced constituent in certain 

 species, the greater portion of several of them consisting of that terpene. 



The species from which it is possible to distil an oil similar in character 

 and composition to ordinary " turpentine " were, at the time of their investi- 

 gation, scientifically undescribed, and in order to distinguish the two principal 

 pinene yielding species, it was decided to apply the names E. dextropinea and 

 E. Icevopinea to them respectively,* so as to clearly indicate the location of 

 either the dextro- or laevo-rotating pinene, and also to point out from which 

 Eucalyptus species the two optically active forms of "turpentine" could be 

 distilled. Other species, such as E. phlebophylla and E. Wilkinsoniana, might 

 also be mentioned in this connection. 



Coniferous trees from which an oleo-resinous exudation, suitable for 

 " turpentine " production, could be derived, hardly occur in Australia, and it is 

 only from one tree (Agathus robusta] the " Queensland Kauri," that it would be 

 possible to prepare " turpentine " commercially, f The resinous latex of this tree 

 contains about 14 per cent, of terpenes corresponding in composition to ordinary 

 turpentine, but unfortunately the trees are too sparsely distributed and too few 

 in number to enable an industry to be established in this way, even if other 

 conditions did not operate adversely. 



If it is desired, therefore, to produce Australian " turpentine " from 

 indigenous trees, other sources of supply must be sought, and to this end we 

 suggest the above species of Eucalyptus for this purpose. By the application of 



* In this naming of species on a chemical constituent we follow Smith in Trans. Linn. Soc., in, 286 (partly) > 

 who, soon after the foundation of Australia, named the " Sydney Peppermint," Eucalyptus piperita, on account 



of certain constituents in the oil, as indicated by the odour. 

 f See Research on the Pines of Australia, Baker and Smith, p. 386. (Technical Education Series, No. 16.) 



