BUTYL ESTER OF BUTYRIC ACID. 465 
Butaldehyde, perhaps the parent substance of this ester, 
is present in most crude EKucalyptus oils, and is one of the 
constituents which give to unrectified oils a somewhat 
objectionable odour. The formation of the ester might 
perhaps be accounted for by a rearrangement in the alde- 
hydic groups of two molecules of the butaldehyde. Normal 
butyric acid has already been identified as occurring in 
small quantity in several of these oils, and this acid was 
probably derived from the hydrolysis of the ester, because 
a corresponding change does take place when the oil of 
EB. Perriniana has been stored for a sufficiently long time. 
The material of EH. Perriniana from which this oil was 
distilled, was collected at Tingiringi Mountain, southern 
New South Wales, in September, 1913. The crude oil was 
rich in eucalyptol, but phellandrene was not detected at 
this time of the year. The general characters of this oil 
agreed with those obtained with the material of the same 
species from Strickland, in Tasmania, collected July 1912. 
The analysis of the Tasmanian sample is recorded in a 
paper by Mr. Baker and myself, in Proc. Roy. Soc. Tas- 
mania, October, 1912. 
The abnormally low refractive index of the lower boiling 
fractions of the oil led to the determination of this ester, 
as so low a refractive index as 1°4538 at 16° C., in ordinary 
fractions, had not previously been detected in Hucalyptus 
oils. 
Determination of the Acid. 
The portion of 200 cc. of the crude oil distilling below 
190° C., was boiled with aqueous potash under a reflex con- 
denser for some hours. The aqueous portion was separated 
and distilled, but nothing came over below the boiling point 
of water, so that methyl, ethyl, and propyl alcohols were 
absent. The remainder was evaporated to dryness and the 
potassium salt decomposed by sulphuric acid and distilled 
Dp—December 2, 1914. 
