54 Volatile Oils. 



from five species of Melaleuca. Of the Eucalypti, the species 

 most common within a few miles of Melbourne are E. Ros- 

 trata, E. Odorata, and E. Viminalis. In these, like all others 

 of this genus, the leaves are the principal source of oil, the 

 branchlets containing very little oil, the bark and roots none. 

 The yield from these three species is very scanty. Experi- 

 ments made at different periods of the year upon leaves 

 obtained from the same locality gave results exactly alike. 

 The following facts, however, will show that soil and position 

 have something to do with both the quality and quantity of 

 the product. 



In experimenting on E. Rostrata, I found that the plants 

 grown on high ground gave an oil of a dark amber colour, 

 possessing an agreeable aromatic flavour, and having the 

 aroma of carra ways. The yield from 100 lbs. of the fresh 

 gathered leaves was 1 oz. drs. Specific gravity 0*918. 

 Those grown on low and marshy soil yielded an oil of a pale 

 yellow colour, in appearance and smell similar to that 

 yielded by E. Odorata, the quantity being 9 J drs. to 100 lbs, 



E. Odorata. 



Leaves obtained from trees growing on elevated spots 

 yielded 4 oz. 1\ drs. from 100 lbs., sp. gr. 0'922 : while leaves 

 from low and swampy lands gave, from 100 lbs. only 5 J drs., 

 sp. gr. 0-899. These oils were alike in colour and aroma, 

 being both of a pale yellow, inclining slightly to green, and 

 having a pleasant and agreeable, althoiigh somewhat cam- 

 phoraceous, aroma. 



E. Viminalis. 



That obtained from the Botanic Gardens gave only a trace 

 of oil, whilst that procured from the St. Kilda Park yielded 

 half an ounce of oil from 100 lbs. of fresh leaves. 



I find that Dr. Mueller states the range of these three 

 species to be very extensive, so that the results here given 

 cannot be considered final, as they were all obtained from 

 trees growing within a few miles of Melbourne. The 

 quantity of oil obtained from these species, although small, 

 is not without interest, while they cannot, so far as we are 

 at present able to judge, prove remunerative for any pur- 

 pose ; yet the knowledge of these results directs us to other 

 species. 



I should observe that in all the Eucalypti the oil-cells can 

 be made visible b} r means of transmitted light, and that a 

 practised eye can determine the probable yield of oil by the 

 greater or less degree in which the oil-cells are shown by 



