42 HENRY G. SMITH. 



14 and 27. In many species the ester is most probably 

 geranyl-acetate. 



The results have been classified in groups. Those of the 

 first, or eucalyptol oils, are arranged according to the figure 

 obtained by multiplying the refractive index by ten times 

 the solubility; those of the other groups are in alphabetical 

 order. If the perfumery oils like E. Macarthuri and E. 

 citriodora are omitted, then nearly all those oils which 

 consist principally of eucalyptol and pinene, without phel- 

 landrene, (with the exception of E. Risdoni and E. amyg- 

 dalina) have a refractive index over 1*47; those not reach- 

 ing that figure are only just below. The specific gravities 

 of the oils in this group are, in most instances, above 0*91. 

 The solubility in 70i alcohol is a useful means of graduating 

 the members of this group. The yields of oil are, of course, 

 a commercial factor, and these can be obtained from the 

 table of yields published in the work previously mentioned, 

 page 273. 



Those oils in which pinene predominates, and in which 

 the sesquiterpene is not pronounced, have also a refractive 

 index over 1*47, but only in one instance did the specific 

 gravity reach 0*91. The comparative insolubility of these 

 oils in 70°/° alcohol sharply separates them from those of the 

 first group. The phellandrene oils all have a refractive 

 index over 1*48, and in some instances over 1*49 or even 

 higher if the sesquiterpene is in excess. Those oils in 

 which the aldehyde aromadendral is a pronounced con- 

 stituent all have a refractive index over 1*48, while some 

 of them exceed 1*49. Aromadendral also occurs in small 

 quantity in many oils of the eucalyptol class, but is not 

 present in sufficient amount to exert much influence. The 

 sesquiterpene oils have, as a rule, the highest refractive 

 indices, exceeding 1*5 in several instances. The solubilities 

 in alcohol of the terpene oils appear to have little distinc- 



