AMYL ESTER OF EUDESMIC ACID IN EUCALYPTUS OILS. 77 



with hydrochloric acid, when a soft paraffin-like substance sepa- 

 rated, this soon became crystalline. The separated oil, after 

 agitating with the potash solution, was saponified with alcoholic 

 potash in the usual way, water added and the aqueous solution 

 acidified, more of the crystalline acid was thus obtained showing 

 that some of the ester had distilled unchanged, it may be 

 mechanically. 



The residue left in the still above 292° C. was agitated with 

 aqueous potash, and on acidifying the alkaline solution a fairly 

 large quantity of the crystalline acid was obtained. On saponifying 

 the portion insoluble in aqueous potash in the usual way and 

 acidifying the solution, only a very small quantity of the crystal- 

 line acid was obtained, showing that the greater portion of the 

 ester had been decomposed by the temperature at which the oil 

 had been distilled. The crystalline substance thus obtained was 

 the acid of the ester occurring in this oil, and on purifying each 

 of the portions obtained as described above, an identical crystallised 

 acid was obtained. No phenols could be detected. 



The purification of the acid was carried out as follows : — The 

 crystalline substance, obtained by acidifying the potash solution, 

 was dissolved in alcohol and boiled with the addition of a little 

 animal charcoal, filtered, and allowed to crystallise. The crystals 

 were separated, dissolved in boiling water, and filtered boiling hot. 

 On cooling the acid was deposited in crystals, recrystallisation 

 from boiling water was repeated two or three times, a product of 

 constant melting point was thus obtained. It is very necessary 

 to obtain the crystals thus, as the impurities present cannot 

 otherwise be removed, and these lower the melting point consider- 

 ably. If purification be carried out as described above, the melting- 

 point of the crystals obtained in any direction will be constant. 

 The same crystals were obtained when the original oil was 

 saponified with alcoholic potash, and also when aqueous potash 

 was used for determining the alcohol. 



The acid is quite white and in general appearance is not much 

 unlike salicylic acid, it crystallises in rhombic prisms and these 



