317 



the statement has been made that at certain times of the year, the yield is 

 greater than that obtainable from the leaves at the same period. 



The results of the investigation on the oil from the bark show it to be identical 

 in composition with that obtainable from the leaves, so that no separation need 

 be made for commercial purposes. With trees of fair size, it should be profitable 

 to steam distil the bark for its oil, that is, if it be considered necessary to cut down 

 the trees in the process of manufacture. The growth of "suckers" from the 

 stumps of the felled trees is, however, somewhat rapid, so that new material 

 would soon be available, and, as shown above, an excellent oil is obtainable from 

 this young foliaceous growth. 



The bark was chopped into small pieces, coarsely ground in a mill, and 

 steam-distilled. The yield of oil was equal to 0-12 per cent. 



The crude oil was of a light amber colour, and had a distinct odour of 

 geranyl-acetate. It gave the following results : 



Specific gravity at 15 C. ... ... ... ... = 0-9214. 



Optical rotation a D ... ... ... ... ... -f- 1-2. 



Refractive index at 20 C. = 1-4718. 



Soluble in 1-2 volumes 70 per cent, alcohol. 



The optical activity of the oil was due to the presence of a small quantity 

 of dextro-rotatory pinene. The stearoptene eudesmol, which is a constant 

 constituent in the leaf oil, does not appear to be present in the bark oil. 



The saponification number for the esters in the cold with two hours' contact 

 was 169-5, equal to 59-3 per cent, geranyl-acetate. 



A portion of the oil was then acetylated in the usual way. The saponi- 

 fication number with this acetylated oil in the cold was 198-8, equal to 69-6 per 

 cent, of ester. The saponification number had thus increased by 29-3, so that 

 the free geraniol in the oil was 8 per cent. 



A sample of crude oil from the bark of this species distilled in October, at 

 Wingello, by Mr. W. J. Quigg, was also investigated at the Technological Museum. 

 It contained a larger amount of ester than did the oil distilled by us, and had the 

 following characters : 



Specific gravity at 15 C.... ... ... ... = 0-9099. 



Optical rotation a D ... ... ... + 1-4. 



Refractive index at 20 ... ... ... ... = 1-4648. 



Soluble in 1-2 volumes 70 per cent, alcohol. 



The saponification number for the ester in the cold with two hours' contact 

 was 195, equal to 68-2 per cent, geranyl-acetate. 



The saponification number for the acetylated oil, also in the cold, was 224, 

 equal to 78-4 per cent, of ester, an increase in the saponification number of 29, 

 representing about 8 per cent, of free geraniol in the crude oil. 



A commercial sample of the bark oil of this species, presented to the Museum 

 by De Meric Ltd., George-street, Sydney, had the following characters : 

 Specific gravity at 15 C. ... = 0-9218. 



Optical rotation a D ... ... ... ... + 1-2. 



Refractive index at 20 ; 1-4711. 



Soluble in 1-2 volumes 70 per cent, alcohol. 



The saponification number in the cold with two hours' contact was 169, 

 equal to 59-2 per cent, geranyl-acetate. 



This Eucalyptus is one of the very few species of the genus from which an 

 essential oil can be distilled from the bark, and, so far as at present known, it is 

 the only Eucalyptus bark of commercial value for oil production. 



