AND THEIR ESSENTIAL OILS. 41 



CHEMISTRY. 



Essential Oil. This material for distillation was 

 obtained at Mt. Wellington, at an altitude of about 2500 

 feet. It was collected in July, 1908; and this being, the 

 depth of winter, the yield is probably less than would be 

 obtained generally, as this species most likely follows the 

 rule in this respect. The principal constituents in the oil 

 of this species are dextro-rotatory pinene and eucalyptol, 

 over 60 per cent, of the latter constituent being present. 

 Phellandrene does not occur, nor were either eudesmol, 

 piperitoiie, or aromadendral detected. The ester is pro- 

 bably geranyl-acetate largely, as the greater portion was 

 saponified in the cold with two hours' contact. The small 

 amount of high boiling constituents in the oil of this 

 species causes it to have a specific gravity below 0'91 at 15 

 C., while the presence of the pinene in rather large excess 

 gives a somewhat high dextro-rotation. The rectified oil, 

 however, is practically colourless almost water-white 

 and it has, for an ordinary Eucalyptus oil, a very agreeable 

 odour, and no objectionable flavour. The average yield 

 of oil from leaves with terminal branchlets was 1'132 per 

 cent. The crude oil was reddish in colour, as is usual with 

 oils of this class when the leaves are distilled from iron 

 digesters. Its specific gravity at 15 C. 0*9088; rota- 

 tion a D = + 11-8; refractive index at 23 C. = 1'4638; 

 and it was soluble in 5 volumes 70 per cent, alcohol by 

 weight. 



On rectification, the usual amount of acid water and 

 volatile aldehydes, from oils of this class, were obtained 

 below 165 C. (corr.). Between 165-174 C. 54 per cent, 

 distilled; between 174-193 C. 36 per cent.; the ther- 

 mometer then quickly rose to 230, and between that 

 temperature and 246 C. 5 per cent, distilled. 



R/ ^ t Sp. Gr. at Ref. Index 



&D - Ifio C. at23r. 



First fraction +15-7 ... 0'9001 ... 1-4599 



Second fraction ... + 6-4 ... 0-9165 ... 1-4602 



Third traction ... 0-9285 ... 1-4836 



The eucalyptol was determined in the oil distilling below 

 193 C. by the resorcinol method, which result showed 

 that 63 per cent, of that constituent was present in the 

 crude oil. The saponification number of the ester and free 

 acid = 18'3. In the cold, with two hours' contact, it 

 was 10-7, equal to 3*7 per cent, of geranyl-acetate if cal- 

 culated for that ester. 



