THYMOL, MENTHONE AND MENTHOL FROM EUCALYPTUS OILS. 41 



great resemblance to that obtained from the "Peppermint,'* 

 Mentha piperita, which grows in England. 



The species from which this "Peppermint oil" had been 

 distilled was Eucalyptus piperita, a tree which must have 

 been, at that time, quite common around Sydney. 



Piperitone appears to be more generally distributed in 

 the oils of species growing in the eastern and south-eastern 

 portion of Australia and Tasmania, where the members of 

 the whole group are generally known as "Peppermints." 

 This ketone is usually associated in these oils with the 

 secondary alcohol piperitol, and we have isolated this 

 alcohol from the oil of E. radiaia, and have determined its 

 chemistry. 



On the mountain ranges of the Main Divide the members 

 of the "peppermint" group of Eucalypts form a large pro- 

 portion of the natural vegetation, and are distributed over 

 hundreds of square miles of country. 



It is now recognised that all the principal constituents 

 found in Eucalyptus oils increase in amount through a 

 range of species, until a maximum is reached in one of 

 them. Piperitone is no exception to this rule, and Euca- 

 lyptus dives, the "Broad-leaved Peppermint," appears to 

 be the species in which it reaches the maximum content. 

 The yield of oil from this Eucalypt is also large, from 3 to 

 4 per cent., according to the time of year, and provided 

 the primary distillation has been somewhat extended, say 

 from 6 to 8 hours, the oil will often contain as much as 

 from 40 to 50 per cent, of piperitone. It is thus evident 

 that this ketone could be obtained in great quantity, par- 

 ticularly as the species is one of the most plentiful of all 

 the "Peppermint" group. 



The remainder of the oil, which consists largely of 

 phellandrene, would be useful for mineral separation by a 



