Chemistry of Essential Oils

N. O. GEAMINE^ 87

According to Dymock
l
and Schimmel
2
this oil has the following char-
acters :—
Specific gravity 0*905 at 29°
„ „ 0-915 „ 15°
Optical rotation - 4° to + 34° 38'
The oil contains phellandrene.
Hofman 3 has investigated the properties of an essential oil distilled
from a species of Cymbopogon, which, in the absence of a more precise
determination, he calls Cymbopogon javanensis. It is a light yellow oil,
with a pleasant sweet smell, resembling more the palmarosa type than
the lemon-grass kind. An analysis of the oil yielded the following
results:—
Specific gravity
Optical rotation
Refractive index.
Acid number
Saponification number
Geraniol content.
Free alcohols

. 0-9747

- 2° 54'

1-51352

1-25

30-9

48-2 per cent.

33-9

Esters.. -. 14-3

Methyl -isoeugenol 30-4

0-968 to

• 10° 52' -
  1-4995 „
  1-9
  8-4

0-9673

- 11° 4

—

0-9

16-8

37-3

Among the aldehydes isolated from the oil methyl-vanillin was found,

which had never previously been found in an essential oil. Citral,

Z-a-pinene, and methyl-isoeugenol are also present in the oil.

OIL OF ANDROPOGON GBYLLUS.

The green portions and root of Andropogon Gryllus (A. Ischaemum)

yield up to 1 per cent, of essential oil, which has been examined by

Schimmel & Co.

4

Two samples had the following characters:—

Specific gravity

Optical rotation

Refractive index

Acid value

Ester value.

,, „ (after acetylation)

It has no value as a perfume oil. It contains about 10 per cent, of

an alcoholic body calculated as C 10 H 18 O.

OIL OF ELIONUKUS TRIPSACOIDES.

This grass is a native of Central America, extending from Mexico to

the United States of Colombia and Venezuela. It is very abundant in

Bolivia. It belongs to the same tribe of grasses (Andropogonece) as the

ginger-grass, lemon-grass, citronella, and vetivert, but differs from the

genus Andropogon in the spikes of flowers not bearing awns, and ap-

proaches Eottboellia in the slender spikes, differing from it in having

hairs on the rachis of the spikelets, and on the stalks of the flowers,

being, in fact, intermediate between the two genera. The odour of the

root approaches that of vetivert, or cuscus, but is of a somewhat sweeter

and Jess penetrating character.

It is interesting to find that it is not the only aromatic species of the

genus, since in South Africa a species occurs which has a thyme-like

odour, whence its name Elionurus thymiodorus. It occurs in the

(^1) Pharmacographia Indica, vi., 564.
(^3) b. WeekbL, September 6,1919.
(^2) Bericht, April, 1892, 44.
(^4) Bericht, 1917, 8 ; 1918, 5.