Vol. XXVII. 

 igio 



] Field Naturalists' Club — Proceedings. 6i 



yield timber of equal bulk to that of an oak 200 years old. The 

 oil industry should be developed, but producers must learn to keep 

 the oil of each species distinct. The chemical constituents were so 

 varied that by mixing the oils many of them were ruined for 

 practical uses. There need be no difficulty in distinguishing the 

 different groups of species yielding the various constituents, for it 

 was found that precisely what kind of oil would be yielded could 

 be predicted from an examination of the venation of the leaves. 

 Thus those species in which there was a very indistinct marginal 

 vein, and the secondary veins were almost at right angles to the 

 midrib, were richest in eucalyptol, while as the veins branched off 

 at a more or less acute angle to the midrib so the yield of 

 eucalyptol became less and phillandrene became more and more. 

 This constituent had been some trouble to the makers, as oils 

 containing a large percentage of it were considered worthless, but 

 it had recently been discovered that after numerous trials of 

 other oils a phillandrene eucalyptus oil was the one best suited 

 for use in a certain process for recovering concentrates in mining, 

 hence its value must rapidly improve. The Silver-leaved Iron- 

 bark of Queensland, E. Staigeriana, yielded citral, a constituent 

 from which ionone is obtained, and which is the basis of the 

 artificial perfume of violets, so that this is a very valuable 

 eucalyptus oil. Then there were other constituents of great 

 value. The Lemon-scented Gum of Queensland, E. citriodora, 

 depended for its odour on the citronellal contained in its oil. 

 This was now being used as a substitute for citronella oil in soap- 

 making, &c. In another species, E. camphora, endresol was a 

 prominent constituent ; no use had yet been found for it, but he 

 had no doubt but that it would prove of great value. Perhaps 

 the widest field which he could see at present for a eucalytus oil 

 was that of the Silver-topped Stringybark, which was almost 

 pure turpentine, and he ventured to say that when the yield of 

 turpentine from the pine trees of America fell off owing to the 

 destruction of the forests, Australia could easily provide the 

 world with turpentine. He was glad to see such excellent 

 products being made from the gum-trees of Victoria as was being 

 done by Cuming, Smith and Co. at their works at Warburton. 

 There acetic acid, ethyl alcohol, formalin, tar, pyroligneous acid, 

 and many other chemicals were being manufactured, while the 

 resulting charcoal, at first regarded as a waste product, was now 

 almost the most valuable, being in great demand by the users of 

 the new suction gas engines. Regarding the capabilities of the 

 gum-trees from a timber point of view, he said that in this respect 

 they were also invaluable. For many purposes no better timber 

 could be obtained in the world. The breaking strain of the 

 Victorian giant gum, Eucalyptus regnans, had been proved to be 

 better than that of the far-famed hickory of America, and for 

 coach-building purposes it could not be excelled. Their 



