AUSTRALIAN MELALEUCAS AND THEIR ESSENTIAL OILS. 207 



to belong to the aliphatic series. The odour is somewhat 

 pleasant, although weak in this respect. When diluted 

 with alcohol and spread thinly on a watch glass, the odour 

 becomes a little more defined and delicate and remains 

 persistent for several days. 



This appears to be the first time that a substance of this 

 nature has been noticed occurring in the leaf oils of plants, 

 and it is only very recently that similar constituents have 

 been determined as existing iu the odoriferous oils of cer- 

 tain flowers. In "Die atherischen Ole " of Gildemeister 

 and Hoffman, 2nd edition, p. 416, these substances are 

 referred to, and the statement is there made that up to the 

 present time (1910) they have only seldom been observed, 

 but it is presumed that with extended investigations they 

 will be more frequently found. Two of these alcohols are 

 mentioned in the work referred to, NerolidoV found in the 

 higher boiling portions of Orange flower oil, which had, 

 boiling point 276-277°, 128-129° (6mm.); spec. gr. 0'880; 

 rotation a D + 13°. 32; and Farnesol which occurs in the oil 

 of Ambrette seeds, in Linden flower oil, in the oils of the 

 flowers of various kinds of Acacias, and probably also in 

 Rose oil. Haarmann and Reimer, 2 show the boiling point 

 to be 160° (10 mm.); sp. gr. at 18° 0*885 ; w n 1*488; rotation 

 a D + 0°. An investigation has just been undertaken by 

 M. Kerschbaum on farnesol. 3 This author assumes that 

 farnesol acts as a fixing material for the more volatile con- 

 stituents of the flower, and attributes the sweet scent of 

 Linden flowers to the presence of these sesquiterpene 

 alcohols, which delicate odour is brought out by extreme 

 dilution assisted by the oxidising influences of the air. 



1 Hesse and Zeitschel, Journ. f. prakt. Chem. n, 66 (1902), 504. 



2 Patent No. 149603 and Chem. Zentralbl. 1904, i, 975. 



3 Ber. Deut. Chem. Gesell., 1913, p. 1732. 



