76 PROCEEDINGS OF SECTION B. 



of the Coniferae also. The oil of this Danvinia is so closely related 

 in chemical constituents to that of Eucalypliis Macarthiiri that 

 the consideration of the products of both trees may be taken 

 together. 



(b) Eitcalyptus Macarfhuri grows plentifully in the Wingello 

 district of this State, and is also a common tree in the neighbour- 

 hood of Bowral. It grows in proximity to Paddy's River as a 

 fine foliaceous tree, and is there known as " Paddy's River Box." 

 The oil distilled from its leaves has no resemblance to ordinary 

 Eucalyptus oil, as it consists very largely of the acetic acid ester 

 of geraniol, free geraniol being also present. It is thus closely 

 related to the oil of D. fasciadaris. The amount of ester varies 

 between 60 and 75 per cent, in the leaves of old trees, the free 

 geraniol diminishing in amount as the ester increases. Free 

 geraniol to the extent of 12 per cent, has been found. All the 

 determinations which have been so far made show the ratio 

 c ombined geraniol ^ ^ between -^h and -<hh so that the increase 



total geraniol ^ " "' 



of ester is largely at the expense of the free geraniol. The 

 following results show this clearly :— One sample of oil con- 

 taining 74-9 per cent, of original ester was acetylised, and the 

 total ester then formed was 82-6 per cent., indicating only 

 about 6 per cent, of free alcohol to be present. Another sample 

 containing 65*8 per cent, of naturally formed geranyl-acetate 

 showed total ester on acetylising to be 80-5 per cent., or nearly 12 

 per cent, of alcohol. 



Neither Eucalyptol nor Phellandrene occur in the oil of this 

 Eucalyptus, so that sophistication with other Eucalyptus oils 

 could be easily detected. A minimum content of 60 per cent, 

 ester could, however, be taken as a standard, because no natural 

 oil has yet been determined with less than that amount of ester, 

 but perhaps a better standard would be the total amount of ester 

 formed on acetylising. 



The following constants are those of a fair sample of the crude 

 oil of this species of Eucalyptus : — 



Specific gravity at 15X = 0-9174 



Optical rotation fl^ 



Original ester 



Ester after acetylising 



Refractive index at 22°C. . . 



Soluble in IJ volumes 70% alcohol by weight. 

 Messrs. Schimmel & Co. have determined the ester values in 

 two consignments of this oil with the following results : — 



(1) Ester content before acetylising, 63-7 ; after, 85*2% 



(2) „ „ „ „ 71-68; after, 80-5% 

 No. 2 was rectified in vacuo and on acetylising it gave 82.2 



per cent, ester. 



It may thus be assumed that natural oils of this species of 

 Eucalyptus should always show about 80 per cent, of ester after 

 acetylising, but sufficient work has not yet been done to enable 

 this minimum to be fixed with certainty. 



= -f 0-69° 

 = 68-4o/„ 

 = 81-02% 

 = 1-4712 



