CRYSTALLINE CAMPHOR OF EUCALYPTUS OIL. 95 



that are necessary to this alteration, and this probably accounts 

 for the fact that the oils of the globulus group are always dextro- 

 rotatory, as it is found that when the maximum of eucalyptol has 

 been reached in the oils of E. piperita, E macrorhyncha, etc., that 

 the oils are always dextrorotatory, and in about the same propor- 

 tion as is found in the oils of the globulus group. As a result of 

 experiments on the terpenes, by Armstrong and Tilden ; T they 

 arrive at the conclusion that American turpentine contains a sub- 

 stance which either has a less dextrorotatory power or is laevo- 

 rotatory, and which is more readily polymerised than its chief 

 constituent. This also appear to be the case with the pinenes of 

 Eucalyptus oils. 



If eudesmol is the intermediate stage in the formation of 

 eucalyptol, we ought to find that those oils which have been found 

 to contain eudesmol in quantity should, at certain times of the 

 year, become rich in eucalyptol, and that has been found to be so. 

 The oil of Eucalyptus camphor a distilled from material sent from 

 Delegate, Feb. 1899, was found to be rich in eucalyptol, the oil 

 much resembling that of E. globulus, eudesmol was only present 

 in small amount at that time of the year. This is probably 

 the case with E. Smithii also, and it is to be expected that the 

 oil from this tree will be found rich in eudesmol at certain times 

 of the year, as when distilled only a small quantity was present, 

 but the maximum eucalyptol had been practically reached at that 

 time, and 97 per cent, was obtained on redistillation boiling below 

 180° C. so that the constituents boiling at a high temperature 

 were practically absent. The crude oil had almost the same specific 

 gravity as the large fraction, and the first portion distilling was 

 almost as rich in eucalyptol as the last portion. 



Experimental. 

 Preparation of the pure Eudesmol. 

 The oil of Eucalyptus macrorhyncha was taken for the prepar- 

 ation of this camphor, but any oil rich in eudesmol, as E. camphora, 

 would do as well. The constituents boiling below 188 - 190° C. 

 1 Chem. Journ., xxxv., 733. 



