DARWINIAS OF PORT JACKSON AND THEIR ESSENTIAL OILS. 165 



(b) Chemistry of the Oils. 



The Essential Oil of Darwinia fascicular is. 



This oil was obtained by steam distillation on fresh material. 

 When first distilled it is reddish-brown in colour, very mobile, 

 with a somewhat strong odour, which when diffused is pleasant. 

 The principal constituent of this oil is the important ester geranyl- 

 acetate. When placed in a freezing mixture a small quantity of 

 a stearoptene separates, but it is difficult to remove, and was not 

 obtained in a separate condition. The specific gravity of the 

 crude oil was *9154 at 19° 0. The colour was too dark to enable 

 the rotation to be taken, but this colour being due to a constituent 

 of an acid character is readily removed by agitating the oil with 

 a very dilute solution of aqueous potash. The oil is then of a very 

 light lemon tint and the rotation in 100 mm. tube was 1-2° to the 

 right. 



The yield of crude oil obtained by us from material collected 

 under conditions that would obtain commercially, was *318 per 

 cent., the mean of several distillations on a total of 1,280 pounds 

 of leaves or terminal branchlets. The collections were made in 

 the months of March, September, October, and November. The 

 yield of oil obtainable during these portions of the year is about 

 the same for each month, and the percentage of ester present in 

 the oil is also about the same, with the exception that the Novem- 

 ber oil was the richest in geranyl-acetate. 



The material was obtained from shrubs growing naturally 

 at La Perouse in the neighbourhood of Port Jackson. It was 

 somewhat difficult to obtain the material without a predominance 

 of woody stem ; the shrubs, however, lend themselves very 

 readily to clipping, and then grow more compact and bushy. It 

 is to be expected, therefore, that in a state of cultivation (and 

 of course no permanent success can be obtained without cultiva- 

 tion) the yield of oil would be much greater, as a larger quantity 

 of the leafy portion of the plant would be obtainable. That this 

 is so is shown by the fact, that after our September collection we 



