284 



classification was not then available. Chemical investigation demonstrated that 

 the morphological differences which marked these species were specific, and that 

 the " Peppermint " tree, E. -piperita, had even more chemical affinity to the present 

 species than had either E. dives or E. radiata. 



It would not be possible for a mixed oil from these three species (E. radiata, 

 E. dives, and E. phellandra} to give even comparatively constant physical 

 or chemical results, so that if examined at different times and by different observers, 

 little agreement would be shown as existing in the supposed product from one 

 particular species. To illustrate the necessity of keeping the products from 

 distinct species apart, we have tabulated the results obtained with these three 

 species from different localities. 



These oils all contained phellandrene in varying amounts, and it is to the 

 presence of that terpene that the Icevo-rotation of the oil is largely due. 



* Note the marked agreement between these two samples of oil of E. dives, although obtained from widely separated 

 localities. This is due to the time of the year being the same in both instances. 



It may be assumed that during the spring and summer months, the optical 

 rotation of a particular Eucalyptus oil will be somewhat greater than during the 

 winter months, owing to the presence at that time of an increased amount of 

 the particular terpene causing the rotation ; on the other hand, the c.ineol is 

 generally more pronounced during the winter months. 



It is evident that an oil rich in cineol could not be obtained from either 

 E. dives or E. radiata. On the other hand the peppermint ketone, piperitone, 

 which is such a pronounced constituent in the oil of E. dives, could not be profitably 

 extracted from the oils of either E. radiaia or the present species. 



The great differences of solubility in alcohol between the oils of the above 

 three species is also worthy of notice. 



