REFRACTIVE INDICES WITH OTHER DATA OF EUCALYPTUS OILS. 43 



tive importance, with the exception that with those 

 which are somewhat soluble in 80°/° alcohol, the presence 

 of alcohols, esters, aldehydes, or eucalyptol is indicated. 



The oil of E. Risdoni is rich in eucalyptol, but contains, 

 when freshly distilled, a small amount of phellandrene. 

 The saponification number for the esters was 27. There 

 seems to be no just reason why the terpene phellandrene 

 should be objected to when occurring in Eucalyptus oils, 

 any more than the terpene pinene, providing the desired 

 amount of eucalyptol is present also. Dr. Hall of Parra- 

 matta has shown that the objection to phellandrene as such 

 is not warranted by results. It is, however, unusual to 

 find phellandrene present in oils rich in eucalyptol, as the 

 terpene is usually pinene. The other exception to the 

 general rule is the oil of E. amygdalina, (not the oils from 

 its associated species E. radiata and M dives). The oil of 

 this species has always appeared to be an abnormal one, 

 and is worthy of special study; it has, however, many dis- 

 tinctive features by wh ch it may easily be determined. 



It will be noticed by referring to the original figures that 

 most of the oils have increased a little in specific gravity 

 since they were first distilled, those richest in eucalyptol 

 have, as a rule, increased the most, and the formation of 

 an insoluble deposit in those eucalyptol oils like E. globulus, 

 E. pendula, E. oleosa, etc., seems to be associated some- 

 what with this slight increase in specific gravity. 



The refractive indices were taken with a Fuess refracto- 

 meter, true for water, and using a sodium light ; the results 

 were read to minutes of arc only. The crude oils were 

 used in all instances except where otherwise stated. 



The refractive indices of the following constituents 

 occurring in the ordinary types of Eucalyptus oils are : — 



Eucalyptol (Schimmel) 1*45961 



Pinene (Wallach) 1*46553 



