Chemistry of Essential Oils

358 THE CHEMISTEY OF ESSENTIAL OILS

Specific gravity 0-910 to 0-930

Optical rotation + 0° 30' to + 12°

Refractive index 1-4600 to 1-4700 at 20°

Yield 0-8 to 1-5 per cent.

The oil contains from 50 to 70 per cent, of eucalyptol, d-a-pinene,

an unidentified terpene, valeric, butyric and caproic aldehydes, iso-

amyl alcohol, a pineocarvol ester, and a sesquiterpene alcohol which

has been named globulol. This is a crystalline compound melting

at 88*5°. Eudesmol and a sesquiterpene are also present.

OIL OF EUCALYPTUS GOMPHOCBPHALA.

This tree is a Western Australian Tuart tree. Its oil has the fol-

lowing characters:—

Specific gravity 0'876

Befractive index 1*4815

Ester value 25'7

It contains phellandrene.

OIL OF EUCALYPTUS GONIOCALYX.
This tree is known in Victoria as the " spotted gum " or " white
gum/' but in New South Wales it is usually spoken of as " blue gum "»
The oil is bright yellow, of suffocating odour, and has the following
values:—
Specific gravity 0-911 to 0-9125
Optical rotation + 4-3° to + 7-1°
Refractive index 1*4746 at 16°
Yield 0'96 per cent.
It contains 50 to 60 per cent, of eucalyptol, a-pinene, eudesmol, and
valerianie and acetic esters.

OIL OF EUCALYPTUS GBACILIS.
This tree inhabits the same districts as Eucalyptus dumosa, and is
also found in Queensland. Its oil contains a fair proportion of cineol,
and its cultivation has attracted some attention in Victoria. It has the
following characters:—

Specific gravity 0*910

Optical rotation + 1'35°

Refractive index 1-4771 at 16°

Yield 0-9 per cent.

It contains eucalyptol, pinene, and aromadendral.

OIL OF EUCALYPTUS GUNNII.
This tree is the Cider gum of Tasmania, Its oil has the following
values:—

Specific gravity

Optical rotation

Befractive index .....

Saponification value ....

Yield

0-9014

+ 1-5*

1-4752 at 18°

6-7

0-39 per cent.

It contains about 40 per cent, of eucalyptol, d-pinene, Z-phellandrene,
esters, and a sesquiterpene.