30 ESSENTIAL OILS. 



The apparatus required would consist of a still of large dimensions, 

 which might be constructed of sheet iron, with a stout plate at bottom 

 to resist the action of fire. Adapted to this a worm of very moderate 

 size would be found sufficient, as the oils are easily condensed, and for 

 refrigerating purposes a supply of cold water must be available, a small 

 quantity being also necessary for the still. The price at which green 

 leaves, which could be collected by women and young persons, can be 

 delivered at the manufactory, constitutes the chief item in the calcula- 

 tion of expense. To facilitate its estimation the following weights may 

 be stated as the results of actual experience : — a sack, capable of 

 containing 200 lbs. of flour, when closely packed with fresh green leaves 

 only, weighs from 90 to 100 lbs., with Eucalyptus leaves and branchlets 

 together from 50 to 60 lbs. Of the freshly gathered material used for 

 the production of two of the tea-tree oils (linarifolia and genistijolia), 

 the leaves alone amounted in weight respectively to 41 and 48 per cent, 

 of the whole, the stems making up the rest ; from 70 to 80 per cent, 

 may be received as equally applicable to Eucalyptus leaves and 

 branchlets, without involving an important error. The question of cost 

 will be also materially affected, should the residual decoction remaining 

 in the still, after the expulsion of the volatile contents of the leaves, be 

 applicable to some useful purpose. The liquid referred to contains a 

 very considerable quantity of extractive and astringent matter in solu- 

 tion, which might be turned into account in a variety of ways ; but 

 until more is known of its constituents and properties, it would be pre- 

 mature to bring its value into calculation. 



The approximate extent of country covered by the several descrip- 

 tions of vegetation in Victoria is, according to A. J. Skene, Esq., 

 of the Survey Department, morasses, lakes, and lagoons, 402,000 

 acres ; dense mallee scrub, 5,560,000 acres ; mountain ranges 

 densely wooded with gum, 6,225,000 acres ; open timbered country, 

 38,922,000 acres ; open plains devoid of timber, including heaths, 

 4,470,000 acres ; tea-tree scrub, 65,000 acres — Total, 55,644,000 acres. 



From the foregoing figures it will be seen that about 12,000,000 

 acres of land, namely the mountainous tracts, and those covered with 

 rnallee and tea-tree scrub, are densely clothed with myrtaceous vegeta- 

 tion, in the foliage of which enormous quantities of valuable volatile 

 oils are stored. 



The suitability of these substances for the manufacture of varnishes 

 has been freqiiently referred to already ; in addition it may be re- 

 marked, that most, if not all, of the refractory resins which are but 

 little acted on by them at ordinary temperatures yield to their solvent 

 action, when previously fused in the manner commonly practised by 

 varnish makers. 



Gutta percha, which is not affected by a lengthy digestion in the 

 cold, is easily taken up when the temperature is raised, although a large 

 portion appears to be again deposited when the liquid has cooled and 



