AND THEIR ESSENTIAL OILS. 



67 



4. AVERAGE YIELD OF OIL FROM THE 

 SEVERAL SPECIES OF EUCALYPTUS. 



The leaves and branchlets were taken in all cases just 

 as would be done for commercial purposes, and the leaves 

 were as fresh as it was possible to obtain them. The aver- 

 age yield has been given in preference to that of any one 

 distillation, as this mean more nearly represents the com- 

 mie rcial production. The percentage amount has been 

 calculated into weight of oil from 1000 Ib. of material, 

 for the means of ready reference. The results are all of 

 our own distillation from Tasmaniaii material. For com- 

 parative results see the tables for the mainland species 

 published in our work " Research on the Eucalypts " 

 (pp. 273 and 284). It will be noticed that much of this 

 Tasmanian material was collected during the winter 

 months, at a time of the year when the oil is not so abun- 

 dant in the leaf; consequently these results may be con- 

 sidered a minimum yield for the species. 



Yield per 1000 Ib., 



Percentage Leaves and Termin- Dates of 

 Yield. al Branchlets. Colleclion. 



2-32 

 1-90 



1-52 

 1-45 



1-38 



1-28 



1 13 



1-01 



1-01 

 897 

 802 

 793 

 764 

 695 

 657 

 609 



544 



482 

 387 

 163 



E. Risdoui 



E. Mueller! 



E. urnisiera 



E. Perriuiana 



E. phlebophylla. 



E. unialata 



E. regnans 



E. virgata 



E. vernioosa .... 



E. obliqua 



E. taeniola 



E. coccil'era . 



E. virninalis 



E. Rodwayi 

 E. Gunnii .. 

 E.acervula.. 



