Eucalyptus-Oils of Victoria. 201 



As regards compounds other than CjoHigO and CjoHig in 

 Eucalyptus-Oils, Sesqui-terpenes C15H04 appear to be present, 

 and certain Aldehydes have been observed in quantity sufficient 

 to give a characteristic smell to various oils, and in the case of the 

 oil of E. maculata (var. citriodora) Citronellal (Citronellon) 

 and Geraniol are present ; but the chief work to be done in 

 the immediate future ought to be confined to characterising and 

 isolating the great vai'iety of isomerides of the two main 

 substances CjoHigOand CjoHj^. That to do this will be no 

 light undertaking may be gathered from the study of Wallach's 

 woi'k, although he has so simplified the confusion existing as to the 

 number of Terpenes and their derivatives. The closeness of the 

 boiling points of Cineol, Limonene and Phellandrene shows that 

 the method of fractional distillation can give but little help 

 towards even a preliminary separation of a Eucalyptus-Oil into 

 separate chemical compounds ; and a brief account of two series 

 of systematic fractionations, carried out on two typical oils, will 

 make this clear. As it is important to realise that other methods 

 of separation will have to be resorted to in working out the 

 chemistry of the Eucalyptus-Oils, as has been done in certain 

 cases by Wallach, the following tables are given to show the 

 amount of separation achieved by a thorough fractionation. Of 

 the two typical oils chosen the first was of the Terpene type, with 

 low density and high negative specific rotation, and the second of the 

 Cineol type, of high density and small positive specific rotation. To 

 secure steadiness in the fractionations a special apparatus was put 

 together, consisting of a copper flask of 350 c.c. capacity, with 

 brazed joints and a neck 12 cm. long and 19 m.m. diam.; this 

 was inclosed in a cubical chamber of asbestos-millboard of 16 

 cm. edge ; into the neck of the flask was inserted by means of a 

 thin perforated cork a I— tube contracted for insertion in the 

 flask, the large limb of the I— tube was 23 m.m. diam. and the 

 side tube 5 m.m. The I— tube was enclosed in a wooden 

 chamber with a mica-front, through which could be read the 

 fractionating thermometer divided into i°C., wholly immersed in 

 the wide limb of the I— tube. The burner, which heated the 

 cubical asbestos-chamber, was protected from draughts by a sheet- 

 iron case. The apparatus was found to attain the desired end of 



