36 R. GREIG-SMITH. 



of eucalyptus oils, the purer medicinal oils, the cheaper 

 forms used for flotation purposes and those used for per- 

 fumery. The chemistry and economic uses of these have 

 been investigated by H. G. Smith, who has really put them 

 upon a sound basis and has done some really valuable work 

 with them. Most of his work has appeared in the pages of 

 this Journal. In 1902 he showed how the pure medicinal 

 oils can be obtained in the ordinary country still by frac- 

 tional distillation, that is by removing the distillate that 

 comes over in the first hour from the remainder. The pure 

 oil comes over first, the rest is contaminated with phenols. 

 Twelve years afterwards, his researches bore their first fruit 

 when the distillers began to fractionate. The practice 

 enables the pure oil to be obtained from a greater number 

 of species. 



Leaves from the various groups of Eucalyptus give differ- 

 ent oils upon distillation, that is, the ethereal products are 

 mixtures chiefly of cineol or eucalyptol and of geraniol in 

 varying proportions. Those oils in which geraniol pre- 

 dominates are capable of being utilised in manufacturing 

 perfumery, geraniol and citronellol being the chief ingredi- 

 ents in 'Otto of Roses.' The shortage of perfumes caused 

 by the war has induced our manufacturers to utilise the oils 

 obtained from the geraniol group — Eucalyptus Macarthuri, 

 Callitris tasmanica, and Darwinia fascicularis. The 

 exploitation of our natural oils for perfumery should be 

 assisted, and there is need of scientific research in develop- 

 ing new fragrant compounds from the lesser known com- 

 ponents of the essential oils. Mr. H. G. Smith informs me 

 that he has in view the production of vanilla from the 

 common Tea-tree, Melaleuca bracteata, the leaves of which 

 contain 1 % of methyl-eugenol. If one of the methyl groups 

 could be replaced by hydroxyl, we should obtain eugenol, 

 which by oxidation yields vanilla. In fact with regard to 



