4i8 



In ;i paper read by one ol us before the Roy. Soc. N.S.W., Nov., 1901, the 

 name Aromadendrene was suggested for this sesquiterpene. 



A sample of the sesquiterpene was similarly prepared from the oil of E. 



Bailey ana. The constants were in agreement with those recorded above, with 



the exception that the sesquiterpene was laevo-rotatory. It boiled at 123-125° C. 



at 10 millimetres; had specific gravity at 15° C. = 0-9240; optical rotation a D 



-3-7°; and refractive index at 20 = 1-4964. 



The characteristic colour reactions will detect the presence of this ses- 

 quiterpene in many crude Eucalyptus oils. It can also be shown by this method 

 to occur in that of Angophora lanceolata. 



The Paraffin Stearoptenes of Eucalyptus Oils. 



The first member of the paraffins (probably belonging to the aliphatic series) 

 occurring in the Eucalvpts was isolated from the crude oil of E. acervula, 

 Hook.f., the "Red Gum" of Tasmania. This substance was first described 

 in' a paper published by us in the Proc. Roy. Soc, Tasmania, October, 1912. 

 This paraffin is a saturated hydrocarbon, and probably belongs to the C n H, n + 

 2 group. It resembles in appearance, odour on ignition, chemical behaviour, 

 and general characters, the paraffin derived from mineral oils, generally known 

 as " paraffin wax." 



When finally purified, the stearoptene was perfectly white, of a paraffindike 

 nature, and without odour ; on burning, the odour was identical with that of 

 ordinary paraffin when similarly heated and ignited. The melting point was 

 55 to 56° C, determined by the capillary tube method in water, and in 

 other ways. 



Under the microscope it was seen to be crystalline, and when melted 

 and allowed to slowly cool, the crystals polarised in colours. They were not very 

 symmetrical however, but vermiform, often tending to the shape of the letter S. 

 When dissolved in carbon tetrachloride, and bromide added, the colour was 

 not removed ; it was thus a saturated substance. Concentrated sulphuric 

 acid had no action upon it in the cold, nor did the usual oxidising mixture 

 of potassium bichromate and sulphuric acid act upon it in the cold, and only 

 slightly on continued boiling. Concentrated nitric acid appeared to have no 

 action in the cold, and it was but slowly attacked on boiling, acting in this 

 respect similarly to the ordinary paraffins. A solution of potassium permanganate 

 in the cold had no action on it after many days. 



Although the paraffin was isolated from the oil of E. acervula, from 

 material collected from two different localities in Tasmania, yet the melting point 

 for both samples was identical. The melting point, 55 to 56 C, cannot, however, 

 be taken as that of Eucalyptus paraffins generally, and the corresponding 

 stearoptene isolated from the oil of E. Smithii, melted at 64° C. (See paper 

 Roy. Soc, N.S.W., July, 1913.) 



It is thought that these paraffins probably consist of two or more homo- 

 logues, and this is suggested from the results obtained with the oil of E. acervula, 

 which apparently contained a second paraffin, liquid at ordinary temperatures. 

 The higher melting point of the stearoptene from E. Smithii, over that from 

 E. acervula, is perhaps one distinguishing feature between the oils of the 

 different groups. 



