NEW AROMATIC ALDEHYDE OCCURRING IN EUCALYPTUS OILS. 291 



crystalline mass on porous plate, and decomposing with sodium 

 carbonate. The separated oil was well washed and then steam- 

 distilled ; 33 cc. of the aldehyde was thus obtained from a litre of 

 crude oil, equal to 3-3 per cent. The aldehyde was slightly 

 yellowish in tint, very mobile, and had a not unpleasant odour, 

 being more aromatic than cuminaldehyde. It is soluble in the 

 usual solvents for such substances. 



Specific gravity of the aldehyde. — The aldehyde was carefully 

 cooled to 15° C. in a pyknometer standardised at 15° C. The 

 specific gravity was 0*9478. Another determination in a different 

 pyknometer gave 0*9476, this was also cooled to 15° C, this gives 

 a mean specific gravity of 0'9477 at 15° C. 



Specific rotation of the aldehyde. — The rotation of the aldehyde 

 in a 100 mm. tube at 22° C. was - 46-6°, thus the specific rotation 

 is [a] D -49-19°. 



Preparation of the oxime. — The aldehyde was dissolved in alcohol 

 a saturated aqueous solution of hydroxylamine hydrochloride 

 added, and then a solution of sodium carbonate. This was after- 

 wards heated some time at about 80° C. and poured into water ; 

 the oily substance which separated soon crystallised in fine colour- 

 less crystals, showing faces having a fine lustre. The crystals 

 were then drained on a pcrous plate, when they were obtained 

 almost pure. The crystals were purified from alcohol until of 

 constant melting point. The pure oxime melted at 84° 0. When 

 the base was separated with caustic potash instead of sodium 

 carbonate, identical crystals weve obtained, but the oily product 

 was much darker and the yield of crystals was not so large. 



This is the only aldehyde of this character occurring in this 

 class of oils, as several of the higher boiling fractions from various 

 oils were added together, including those of E. cneroifolia, E. albens, 

 and E. Woollsiana. The aldehyde was extracted with acid sodium 

 sulphite in the usual way, purified, and the oxime formed ; this 

 oxime also melted at 84° C. 



