Chemistry of Essential Oils

346 THE CHEMISTEY OF ESSENTIAL OILS

OIL OF EUCALYPTUS ALBENS.

This tree is found principally in South Australia, Its oil has the fol-

lowing characters:—

Specific gravity.0-9044

Optical rotation.- 6-5°

Refractive index.1-4780 at 20°

Saponification value 8-5

Eucalyptol..30 per cent.

Yield.... 0*1

The oil contains eucalyptol, pinene, aromadendral, and esters.

OIL OF EUCALYPTUS ACMENOIDES.

This tree is the white mahogany of Queensland and New South;

Wales. The oil contains phellandrene, aromadendrene, pinene (?), and-

eucalyptol. It has the following characters :—

Specific gravity 0-925

Refractive index 1-5065

Saponification value ....... 5*7

Yield 0-09 per cent.

OIL OF EUCALYPTUS AGGREGATA.

This tree is found in New South Wales, the oil having the following;

characters :—

Specific gravity 0-956

Optical rotation + 27-13°

Refractive index 1-5062 at 16°

Ester value.112-2

Yield..0-04 per cent.

It contains d-a-pinene, and the amyl ester of eudesmic acid.

OIL OF EUCALYPTUS AMYGDALINA.
In commerce the oil known as Eucalyptiis amygdalina is understood!
to be an oil containing much phellandrene and very little eucalyptol. It
is an oil having a specific gravity about 0-855 to 0'885 and an optical
rotation of from - 25° to - 80°. This oil of commerce is probably the dis-
tillate from various species, especially from Eucalyptus dives. But as
the oil is one of great importance in commerce, where it is used to a con-
siderable extent for the purpose of " floating" mineral ores in separation,
processes, it is important that the exact nature of the true amygdalina
oil should be understood. The matter has been finally cleared up by
Baker and Smith,^1 who give the following account of the tree and its
oil:—
"Historical.—This eucalyptus was described by Labillardier in his-
Plants of New Holland (1806).
" Remarks.—This name, Eucalyptus amygdalina, has almost since
the beginning of Eucalyptology been associated with the Tasmanian
flora, for it was from Van Diemen's Land that Labillardier obtained his
specimens. It is, however, with much reluctance that we announce that
we have failed to find this tree on the mainland of Australia.
" The tree passing as Eucalyptus amygdalina in the Eastern Stetes^2
1
Eiiealypts of Tasmania (1912), p. 62.
1
Vide under Eucalyptus Australiana..