206 A. R. PENFOLD. 



Although it is very difficult to separate sesquiterpenes 

 in a high state of purity when their boiling points lie at 

 all close, particularly when the quantity available does not 

 exceed 50 c.c, still they appear to have been separated in 

 as pure a condition as is possible. 



As both of them gave similar colour reactions with 

 bromine vapour, halogen and other acids, it was considered 

 only reasonable that the eudesmene would do so even if 

 only a trace of aromadendrene were present as the reactions 

 are so delicate. 



Eudesmene, however, was prepared by two methods from 

 pure eudesmol, M. Pt. 79-80° O. [a],, 20° + 31*07° separated 

 from Eucalyptus Macarthuri, and it gave similar constants 

 to those given by Semmler and Tobias, (Ber. 46, 1913, 2026) 

 and Semmler and Risse (Ber. 46, 1913, 2303). Both these 

 preparations gave the identical colour reactions as described 

 for aromadendrene, except that bromine vapour, besides 

 giving the characteristic violet-crimson and indigo-blue 

 colouration, showed a fine brownish fluorescence in reflected 

 light much resembling a gold ''sol." These colourations 

 therefore are given by both sesquiterpenes and are not 

 distinctive of aromadendrene alone. 



The sesquiterpenes present in the oil are therefore laevo 

 rotatory eudesmene and aromadendrene, and it is remark- 

 able that the rotation of the eudesmene so found naturally, 

 together with dextro eudesmol, should be lsevo rotatory 

 when that prepared in the laboratory is dextro rotatory. 



Determination of the Sesquiterpene Alcohol. 



The residue from the crude oils distilled under reduced 

 pressure, as also the fourth fraction from sample 3/10/20 

 were spread on porous plates for absorption of adhering 

 sesquiterpenes to take place. After about ten days, the 

 hard cakes were dissolved in alcohol, filtered and recrys- 



