Chemistry of Essential Oils

302 THE CHEMISTEY OF ESSENTIAL OILS

OIL OF AGEBATUM OONYZOIDBS.

According to Murat, this member of the Composite abounds in

Annam to an extent which makes it a plague to the cultivators. Dis-

tillation takes place at the beginning of February or March; 500 kilos

of this plant yielded only 27 grams of essential oil; the yield, a very

small one, is therefore 0*0054: per cent.

The oil of Ageratum conyzoides from Annam possesses the following

properties:—

Specific gravity at 15° 0C1-1090

Optical rotation - 1° 20'

Acid No 0-9

Saponification No 12*1

Ester No 11-2

OIL OF HELICHRYSUM ANGKJSTIFOLIUM.

Helichrysum angustifolium yields about 0'08 per cent, of essential

•oil having the following characters :—

Specific gravity 0*892 to 0-920

Optical rotation + 4° 25' „ - 9° 40'

Refractive index 1-4745 „ 1-4849

Acid value up „ 15

Ester „ 39 „ 134

„ „ (after acetylation) .... very variable

OIL OF PABTHENIUM.

Parthenium argentatum yields 0*5 per cent, of essential oil which

has been examined by Alexander, who considers that a higher yield

would be obtained if a suitable distilling apparatus were available. The

plant is a native of Mexico, and the oil is of a faint greenish-yellow

colour, slightly laevo-rotatory, and of specific gravity 0*886. On fractional

distillation it behaved as follows :—

67 c.c. distilled at 17 mm. pressure

From 50° to 60° 17 c.c.

„ 60° „ 80° 20-3 „

„ 120° „ 160° 24-8 „

Residue ........... 5*5 „

The oil contains Z-a-pinene, and a sesquiterpene (?) of specific gravity

<0-9349, specific rotation - 21° 24', and refractive index 1-4960 at 16°.

OIL OF FLEABANE.

This oil, also known as erigeron oil, is distilled from the fresh-
flowering herb, Erigeron canadensis, a plant widely distributed through
North America, and known locally as horseweed, fleabane, butterweed,
Bolt's tail, etc. Only about 0*5 per cent, of oil is obtained, of a light
yellow colour and aromatic odour. The oil has the following char-
acters :—
Specific gravity 0-855 to 0-870
Optical rotation + 52° „ + 81
°
Acid value 0 „ 1-5
Ester ,„34 „ 109
„ „ (after acetylation) 67 „ 108