406 



XXXII, ii)5. From this investigation it was possible to show the differences, 

 chemically, between /•'. Icevopinea and E. macrorhyncha, because the oil of the 

 former dors not contain eudesmol and other constituents which occur in the oil 

 of E. macrorhyncha. These chemical differences are supported in another 

 direction, as the leaves of /:. Icevopinea do not contain myrticolorin, which 

 dye-material occurs in such abundance in the leaves of E. macrorhyncha. The 

 lsevo-rotatory pinene in the oil of E. phlebophylla is also sufficient to discriminate 

 that species from /:. coreacea, although morphologically these two species show 

 great similarity. By similar means it is easy to determine the difference between 

 E. dextropinea and E. pilularis, as the oil of the latter species is always strongly 

 laevo-rotatory in its lower boiling portion, and also contains phellandrene, 

 which terpene is absent in the oil of E. dextropinea. 



The material for the original investigation was obtained from (i) Barber's 

 Creek (now Tallong) ; (2) Currawang Creek (near Braidwood) ; and (3) Nullo 

 Mountain (near Rylstone), all in New South Wales. The material from Barber's 

 Creek, from which the dextro-rotatory pinene was obtained, was botanicallv 

 identical with that of the species from Currawang Creek, and the results of the. 

 determinations of the oils from those localities (over 100 miles apart) indicate 

 that the oils had been distilled from similar material, again emphasising the 

 fact of the comparative constancy of chemical constituents in the oils of 

 identical species. The Rylstone material was quite distinct, and gave an oil 

 also consisting of pinene, but having even a greater rotation to the left than 

 had the pinene of the other species to the right. It was a piece of good fortune 

 to have obtained the material of E. dextropinea and E. Icevopinea at the same 

 time, so that their pinenes could be worked out together. 



The presence of pinene in the oil from E. globulus was detected some 

 time ago. M. Cloez, in 1870,* published the first detailed observations relative 

 to the oil of E. globulus. This research is now of historic interest, from the fact 

 that he obtained a hydrocarbon C I0 H l6 boiling at 165° C, by distilling his 

 so-called eucalyptol with P„0 5 . This terpene he called eucalyptene. After- 

 wards Faust and Homeyerf gave the same name to a terpene from Eucalyptus 

 oil, which, according to them, was a terebenthene, being readily polymerised bv 

 sulphuric acid. Later, Wallach and Gildemeister J stated that the hydrocarbon, 

 eucalyptene, from E. globulus, is identical with dextropinene. 



In 1895 Bourchardat and Tardy§ carried out experiments with the 

 hydrocarbon found occurring in small quantity in the oil of E. globulus, and 

 arrived at the conclusion that it had the properties of the la^vo-rotatorv 

 terebenthene found in French oil of turpentine, but with an almost equal 

 opposite rotation. They gave its boiling point as 156-157 C. ; its density as 

 0-870 at o° C. and 0-865 at I 8° C., and its specific rotation at 15 C. as [a] D + 

 39° C. They gave Riban's determination || for the specific rotation of laevo- 

 rotatory terebenthene as — 40-3° . It appears, therefore, from the results 

 obtained by these authors on this hydrocarbon from the oil of E. globulus, and 

 those obtained in this research on the same hydrocarbon from the oil from 

 E. dextropinea, that these dextro-rotatory pinenes obtainable from members of 

 two distinct groups of Eucalypts are identical bodies, and that the dextro- 

 rotatory pinene from the whole Genus Eucalyptus is a physical isomeride of 

 the larvo-rotatory pinene (terbenthene) obtained from French oil of turpentine, 



* Compt. Rend., 1870, 687, and Journ. de Pharm. et de Chemie, 1870, xii, 201. 



f Ber. 7, 63, 1429. 



} Ann. 240, 2(1=5-284. Abst. Chem. Soc, 1888, 54, 1205. 



§ Compt. Rend., 1895, I2 °. 1417-1420. 



|| Compt. Rend , 78, 788; 79, 314. 



