STRINGYBARK TREES AND THEIR ESSENTIAL OILS. 119 



incorporation was made between the addition of every two or three 

 drops, the pink colour being taken as the end of the reaction. 

 Drying paper as used in the herbarium for drying plants was used 

 for the pressing, as being far preferable to blotting paper, being 

 stronger and quite as absorbent ; a copying press was used for the 

 pressing. The cake was broken up with the point of a knife, and 

 renewal of the paper was continued until oily indications ceased. 

 By this method fairly concordant results were obtained, and the 

 eucalyptol when regenerated was found to have the physical 

 characteristics of that body, and to be almost pure. Duplicate 

 results at least have been taken and the mean given. C 10 H 18 O, 

 H 3 P0 4 was the formula taken in the calculations. For other con- 

 stituents of these trees we refer to two papers on myrticolorin by 

 one of us, and published in the proceedings of this Society. 



4. Summary of Results. 



1. Baron von Mueller's classification of the " Stringybarks " is 

 endorsed. 



2. That an oil having a less specific gravity than 0*910 has 

 been found to exist containing over fifty per cent, of eucalyptol, 

 and answering all the tests laid down in the British Pharma- 

 copsea of 1898, except that of specific gravity. It is thus seen 

 that the specific gravity test for Eucalyptus oil as given in the 

 B.P., if enforced, might be the means of excluding some excellent 

 oils. 



3. That phosphoric acid is not a satisfactory qualitative test 

 for eucalyptol in some crude Eucalyptus oils. 



4. That eudesmol, the stearoptene of Eucalyptus oil, exists in 

 large quantities in the oil of E. rnacrorhyncha and can be readily 

 purified. 



