120 PROCEEDINGS OF SECTION B. 



young material of all eucalyptus species is identical in composition 

 with that cf the mature trees, so that no difiereuce in the quality of 

 the oil would be experienced by working young trees in plantations. 

 Eucalyptus polybractea being one of the " Mallees," it naturally 

 occurs in the shrubby form, and the yield of oil from one-year-old 

 " suckers " is found to be greater than that from the mature leaves, 

 the oil being equally rich in eucalyptol. The natural tendency of 

 Eucalyptus Smithii is to produce big trees, and as such it shows that 

 rapidity of growth common with most eucalypts which acquire large 

 dimensions. I have accumulated much data concerning the rapidity 

 of growth of this species, both from the stumps of fallen trees and from 

 those which have only been lopped. The rapidity of growth of the 

 seedlings of this species under favorable conditions may be demon- 

 strated from the results of one growing in my own garden at Sydney, 

 at an altitude of about 1,500 feet below that of the natural home of 

 the species. Twelve months ago it was a seedling, about 3 inches high, 

 brought from Hill Top. To-day it is over 6 feet high, and since the 

 advent of the warmer weather has grown at the rate of nearly half-an- 

 inch per day ; for several weeks it even exceeded that average, and 

 the lateral branchlets have also grown at a corresponding rate. The 

 leaves appear to be full of oil, and this has the characteristic eucalyptol 

 odour. Many other eucalyptus species give oils rich in eucalyptol in 

 which phellandrene does not occur, but in most cases the jaeld from 

 these is too small to make their distillation remunerative in competition 

 with the more profitable species. 



Since the phellandrene eucalyptus oils have been utlized so 

 largely for mineral separation at Broken Hill and at other places, a 

 considerable industry in the production of these oils has come into 

 existence, and although the amount used is less than 1 lb. of oil 

 to the ton of ore, yet, as enormous quantities of ore are being treated- — 

 in one mine over 1,000 tons per da 3^ — it is readily seen what a large 

 quantity of oil is required for this purpose. Although a very large 

 number of eucalyptus species growing in Eastern Australia contain 

 phellandrene in their oils, yet only a few of them yield the oil in sufficient 

 abundance to make their distillation commercially possible. The 

 greater portion of the phellandrene oils now being distilled is derived 

 from two species belonging to the " peppermint group " of the 

 eucalypts, \\z., Eucalyptus dives, a species which yields up to 3 per 

 cent, of an oil consisting mostly of phellandrene, and a form of Eucalyptus 

 amygdalina, which grows on the highlands of the eastern side of Aus- 

 tralia, which species yields up to 4 per cent, of an oil containing a good 

 quantity of phellandrene and about 30 per cent, of eucalyptol. Other 

 species like Eucalyptus radiata and Eucalyptus Delegatensis might 

 also be worked, although the yield of oil would be less, but then the 

 oliage of the latter species now goes to waste, as the tree is used for 



