Chemistry of Essential Oils

MYKTACE^E 357

Specific gravity 0-892 to 0-900

Kefractive index 1-4873 at 16°

Acid value 4-9

Ester „ 7-5

Yield 0*11 per cent.

It contains d-pinene, phellandrene, eudesmol, and eucalyptol.

OIL OF EUCALYPTUS FASCICULOSA.
This tree is a Tasmanian eucalypt. Its oil contains pinene, eu-
calyptol, and esters, and has the following characters :—

Specific gravity.

Optical rotation ....

Saponification value ....

Refractive index ....

Eucalyptol

0-904

+ 6-3°

22'1

. 1-4789 at 20°
15 per cent.

OIL OF EUCALYPTUS FLETCHERI.

This tree is a New South Wales " Box " tree. It yields an essential

oil having the following characters :—

Specific gravity....0-880 to 0-895

Optical rotation....- 12-8°

Refractive index....1-4881 at 16°

Yield 0-294 per cent.

It contains about 5 per cent, of eucalyptol, pinene, and aromadendral.

OIL OF EUCALYPTUS FEAXINOIDES.

The New South Wales " white ash" yields an essential oil having

the following characters :—

Specific gravity 0*869

Optical rotation - 28-5°

Refractive index 1-4908 at 16°

Yield 1 per cent.

It contains pinene, eudesmol, and about 5 per cent, of eucalyptol, and

probably some citral.

OIL OF EUCALYPTUS GLOBULUS.

This tree, from which a typical eucalyptus oil is obtained, is the

Tasmanian "blue gum". (Blue gum, however, is a name applied to a

number of other eucalypts in New South Wales, Victoria, and Western

Australia.) This plant was discovered by Labillardier in Tasmania in

1792, and introduced into Europe in 1856 by Eamel. It is a native of

Tasmania and Victoria, although found to a certain extent in other

colonies. The fresh leaves yield from '8 to 1*5 per cent, of oil of a

light yellow colour. The fact that this oil was regarded in Europe as

the typical eucalypt yielding a medicinal oil, together with the occur-

rence of such numerous and closely similar species in Australia,

account for the fact that eucalyptus leaves from various trees were

indiscriminately mixed and distilled, the resulting product being

marked oil of Eucalyptus globulus. Hence the difference observed by

various chemists in the properties of this oil. The pure globulus oil,

which is now largely replaced by other eucalyptus oils, has the follow-

ing characters:—