429 



The laevo-rotation of Nos. 4 and 9 is due to the presence of a slightly 

 larger amount of aromadendral than in the other samples. 



The cineol was determined by the phosphoric acid method as carried out 

 at that time, so that the amounts recorded in the table are naturally a little 

 lower than would have been the case if the more modern methods had 

 been adopted. 



It will be observed that with Nos. 6 and 7, derived from general material, 

 the characters were in close agreement, thus following the rule in this respect. 

 The oil from abnormal leaves (No. 3) was of corresponding value, although it 

 contained a little more pinene than that. derived from older trees. Considering 

 the results as a whole there was shown a fairly close agreement between the oils 

 of the whole series, but identical results were only obtained with the two 

 samples of oil from the same tree (No. 9). 



The results of this investigation were published by us in the Proc. Roy. 

 Soc., N.S.W., xxxi, 259. 



Leaf Material for Eucalyptus Oil Distillation, 



(a) FROM NATURALLY GROWING TREES. 



THE most profitable species of Eucalyptus for oil production, considered from 

 a commercial point of view, will be those which, both for yields and quality of 

 oil, can stand the test of competition, so that naturally the continuity of supply 

 enters very prominently into the question, particularly when a permanent plant 

 has been erected. 



In virgin forest country where the growth of Eucalyptus species has had 

 free play, many of them, useful for oil production, acquire large dimensions, 

 particularly species like E. globulus, E. dealbata, E. Smithii, E. Macarthuri, 

 E. citriodora, &c. As only the leaves and terminal branchlets are required by 

 the distiller, such large trees are naturally a disadvantage, the material having to 

 be collected either by lopping off the branches or by felling the trees.* 



Opinion is divided as to which of the two methods is the most 

 advantageous, and at one time considerable lopping of the branches from big 

 trees was carried out. Lopping, however, is dangerous, and men are adverse to 

 climbing tall trees for the purpose, although in Queensland the method is still 

 adopted with E. citriodora. 



More easy collection would naturally be obtained from the " coppice " 

 growth which springs from the short remaining stems of the felled trees, and 

 with many species this is rapidly produced and abundant. 



* The bark of E. Macarthuri has, however, been employed for oil production. 



