154 



J. C. Earl 



Species. 



Eucalyptus 

 radiata. 



Eucalyptus ) 



viminalia. 5 



Eucalyptus \ 



kitsoni. ) 



Leptospernum ~} 



lanigerum { 



Eugenia f 



Smithii. { 



Nature 

 of leaf. 



large 



small 



lari 



small 

 largfe 



Oil-glands. 

 Mean i 



diani. pel 



mnis. c 



.113 - 13 



Percentage yield 



of oil. 

 calc'd. realized. 



.097 

 .113 



.155 

 .075 



.078 

 .091 



1465 



850 



227 

 1090 



960 

 475 



940 



.88 



.92 

 .91 



.86 



.0208 

 .039 



.032 

 .017 



.013 

 .033 



.037 



.82 



- 2.10 ^ 



- 1.03 - 



- .95 - 



- .60} 



- .82* 



■ •"? 

 - »i 



2.70 



1.32 



.85 

 .56 



.36 



The distillations were carried out on fresh material, from a half 

 to three hundred-weights of foliage being used in each case. It 

 will be seen that the agreement is as close as can be expected in view 

 of the difficulty of obtaining a representative sample. 



The method and formula may, therefore, be applied to indicate 

 the approximate yield of oil to be expected from any oil-producing 

 plant. 



Part III. — The Essential Oil of Eucalyptus platypus. 



By J. C. EARL, A.T.C. 



By courtesy of the Director of the Melbourne Botanic Gardens, a 

 supply of the leaves of Eucalyptus platypus, a tree indigenous to 

 Western Australia, was obtained from the Gardens for the purposes of 

 distillation. 



The yield of oil obtained on distillation of the fresh leaves was 1 per 

 cent. 



The oil had the following constants : — 



Specific gravity at 15715° - 0.9045 



Optical rotation in 100 mm. tube at 12° C, «„ +9.1° 

 Refractive index at 20" C, n D - - - 1.4675 



Saponification number ... Q 



Saponification number after acetylation - 24 



Aldehyde-and ketone-content detetermined 

 by absorption with 30 % sodium bisul- 

 phite solution - nil 

 Cineole content by direct absorption with 



50 % solution of resorcin - - - - 59 % by weight. 



