144 H. G. SMITH. 



and after this treatment gives the amount of free acid present. 

 The crude oil, after removal of the free acid, was but slightly 

 coloured, it had a slight rotation to the right, and formed a clear 

 solution with two volumes of 70 per cent, alcohol. 



The oil was distilled in October 1900, and the yield obtained at 

 that time of the year from leaves and branchlets was 0*112 per 

 cent., 500 lbs. of material giving nine ounces of oil. The leaves 

 were obtained from the neighbourhood of Wingello. The yield is 

 only one-third that obtainable from the leaves and terminal 

 branchlets of Darwinia fascicular is, and may be considered as 

 about equal in amount to that obtained for geranium oil (Pelar- 

 gonium sp.J. It would, however, be necessary to cultivate Dar- 

 winia for its oil, but the leaves of E. m.acarthuri are ready to 

 hand. The mode of collection and distillation need not differ in 

 any respect from that followed with ordinary Eucalyptus oil, 

 except that it seems wasteful in the extreme to cut down the trees 

 simply for their leaves, when by topping the trees, fresh material 

 might again be obtained from the same trees in a few years. As 

 the actual cost of obtaining crude Eucalyptus oil per pound from 

 various species is well known, the cost of manufacturing any crude 

 Eucalyptus oil can be calculated, providing the percentage yield 

 (on a commercial scale) of any species is known. The method of 

 preparing the oil of E. macarthuri for market is purely a com- 

 mercial matter, but the saponification of the total ester in the oil 

 takes place in the cold when alcoholic potash is used, the delicacy 

 of the geraniol is thus not impaired in the slightest, as it is 

 unnecessary to use heat, and the stearoptene, (eudesmol), having 

 scarcely any odour does not interfere. The separated oil after 

 cold saponification is light yellowish in colour, its odour is fresh 

 and aromatic, and when diffused the rose odour is very marked. 

 The acetic acid present in the ester might also be recovered if 

 desired. 



It is probable that slight differences may be found in the com- 

 position of the oil at different times of the year, but judging from 

 the results obtained for Darwinia these differences should not be 



