V AND THEIR ESSENTIAL OILS. 175 



alcohol. The slightly larger amount of phellandrene and 

 correspondingly less eucalyptol at this time, accounts for 

 the differences in amount of rotation, in gravity, and 

 solubility to those previously recorded. On rectification, 

 only the usual amount of acid water and volatile alde- 

 hydes came over below 173° C. (corr.). Between 

 173- 184° 82 per cent, distilled, and between 184-195^ 

 11 per cent, distilled. These fractions gave results as 

 follows : — 



The eucalyptol was determined by the resorcinol method, 

 the result indicating 58 per cent, of that constituent in 

 the crude oil. The saponification number of the esters 

 and free acid by boiling was 21"3 ; and in the cold, with 

 two hours' contact, 55. 



The supposed variety hypericifolia gave a light amber- 

 coloured oil, having a somewhat pleasant odour; the aver- 

 age yield was 124 per cent., and the oil agreed in all 

 respects with the requirements for that of E . Risdoni. 



The specific gravity of the crude oil at 15"^ C. = 0'9045 ; 

 rotation aj^ = — 14"6 ; refractive index at 19^ = r4660, 

 and was soluble in 5 volumes 70 per cent, alcohol. The 

 saponification number of the esters and free acid by boil- 

 ing was 23*8 ; and in the cold, with two hours' contact, 3'9. 

 It is thus evident that the main ester in the oil of E. Ris- 

 doni is not geranyl-acetate. 



On rectification, only a few drops of acid water and 

 volatile aldehydes came over below 173° C. (corr.). These 

 aldehydes had no objectionable odour. Between 

 173-1980 94 per cent, distilled. This had specific gravity at 

 150 = 08991 . rotation a^ = — 15"4 ; refractive index at 

 190 = r4641. The comparative absence of high boiling 

 constituents is worthy of notice. 



The eucalyptol was determined by the resorcinol method, 

 and gave 56 per cent, calculated for the crude oil. 



If these results are tabulated it can be seen at a glance 

 how closely the oils agree in general characters, and, allow- 

 ing for the slight increase in eucalyptol and less phel- 

 landrene at the time of distillation, with the type of 

 E. Risdoni also. 



