14 ESSENTIAL OILS FROM THE 



Solubility of Resinous Substances — Continued. 



Name of Resinous 

 Substance. 



Number 

 of ounces 

 avoirdupois 

 soluble in 

 1 imperial 

 pint. 





174 





1-45 





1-16 



Caoutchouc .... 



073 

 073 



Gutta Percha . . . 



o-o 



Remarks. 



About one quarter of the amber 

 soluble ; it must be used in excess 

 to obtain a concentrated solution. 



This resin is soluble only in part, 

 (about 67 per cent.), the remainder 

 gelatinizes and remains for a long 

 time in suspension. These particles, 

 although they swell very much, 

 do not lose their granular form 

 nearly so much as those which 

 form the insoluble portion of 

 copal. 



Obtained by digesting a very large 

 excess, reduced to a fine powder ; a 

 small portion only of the lac being 

 soluble, and that with great diffi- 

 culty. The colour of the solution 

 is pale orange. 



A perfect solution, but very viscid. 



Slightly turbid. The essential oil 

 is capable of liquifying many times 

 this quantity, but the turbidity of 

 the solution increases very much, 

 and it becomes thicker, ultimately 

 refusing to flow. 



Digestion for several days produced 

 no effect. 



Eucalyptus oleosa (Mallee Scrub). — This species of Eucalyptus fur- 

 nishes an essential oil which undoubtedly ranks first in importance 

 amongst those submitted to the jurors. The interest which attaches to 

 it, arises from the fact that greater facilities are offered for collecting the 

 leaves from which it is distilled than is the case with those furnishing 

 the other oils forwarded to the Exhibition. 



The E. oleosa covers the greater part of the vast tracts of level 

 country towards the north-west of Victoria, forming, svith the species E. 

 dumoso (Cunn.), and E. socialis (F. Mueller), the dense masses of vegetation 

 known as Mallee Scrub. Its dimensions require it to be ranked as a 

 shrub, as it rarely exceeds twelve feet in height ; but from the circum- 

 stance that the individuals of the species are clothed with foliage to the 

 ground, and often grow so closely together as to form impenetrable 

 masses of vegetation, an exceedingly large quantity of the leaves can be 

 procured in a short space of time, without moving far from one localit-- 



