PINENES OF THE OILS OF THE GENUS EUCALYPTUS. 197 



Creek. This species was described by my colleague Mr. R. T. 

 Baker, floe, cit.) under the name Eucalyptus dextropinea, a 

 recognition to the science of chemistry for assistance rendered in 

 the determination of species of this important and difficult genus. 



From the results of the determinations of the oils from the 

 leaves of E. dextropinea, from both Barber's Creek and Curra- 

 wang Creek, localities over one hundred miles apart, it might be 

 inferred that the oils were obtained from identical material, and 

 the results again emphasize the fact that the same species of 

 Eucalyptus gives an oil identical in composition, no matter where 

 grown, if collected at the same time of the year. We have other 

 evidence that this is true, and the determination of the oil, together 

 with that of the other chemical constituents of the tree, will be of 

 great assistance in the determination of unknown species. The 

 genus is so prolific in chemical constituents, both crystallised and 

 liquid, that possibly many of the difficulties experienced in the 

 study of the Eucalypts may be effectually removed when the 

 several products of individual trees shall have been systematically 

 investigated by the chemist. The results brought forward in this 

 paper are an instance in point, as the oils of the type species from 

 the three localities possess great similarity ; they all consist prin- 

 cipally of pinene, and in colour, odour, specific gravity, etc., 

 resemble each other most markedly, yet while the pinene from 

 both the Barber's and Currawang Creeks material rotates the ray 

 of light to the right, the pinene from the Rylstone Eucalypt 

 rotates the ray to the left. The Rylstone material was collected 

 under the personal supervision of Mr. Baker. We cannot admit 

 that a tree giving an oil consisting principally of a dextrorotatory 

 pinene having a specific rotation = [a] D + 41'2° is identical with 

 one giving an oil, also consisting principally of a pinene, that is 

 lsevorotatory to even a greater degree, although the d inferences in 

 some of the botanical material may not be very marked. Mr. 

 Baker, however, informs me that the timber of E. Icevopinea is 

 excellent, while that of E. dextropinea is a comparatively worth- 

 less timber. 



