Chemistry of Essential Oils

332 THE CHEMISTEY OF ESSENTIAL OILS

The spice usually known as cloves, and which is generally em-
ployed for the distillation of the oil, consists of the dried unexpanded
flower buds.
The flower stalks, separated from the cloves whilst they are drying,
are also dried and exported, chiefly from Zanzibar and Pemba, and
yield on distillation 5 to 6 per cent, of oil, as against 14 to 21 per cent,
obtained from the buds. The stalks are known in Zanzibar as Vikunia,
and in France as " Griffes de Girofle ".
The dried fruits are occasionally exported, and are known as mother-
cloves. A small amount of essential oil is obtained from them.
Clove buds yield from 14 to 21 per cent, of a heavy essential oil,
having the following characters :—
Specific gravity 1-044 to 1-069
Optical rotation - 0° 20' „ - 2° 30'
Refractive index 1-5290 „ 1*5355
Eugenol (by absorption) 78 to 98 per cent.
The oil is soluble in 1 to 3 volumes of 70 per cent, alcohol.
The following figures represent samples examined by the Imperial
Institute Chemists, the author, and Schimmel & Co., all being of
authentic origin:—

Amboyua.

Seychelles

M

» j

Ceylon

Mauritius

Zan

j

»

ibar

Specific Gravity.

1-0490

1-0470

1-0485

1-0510

1-0510

1-0456

1-0477

1-0514

1-0614

1-0681

1-0590

1-0570

1-0550

1-0525

1-0530

Refractive

Index.

1-5305

1-5295

—

1-5320

1-5325

_

1-5345

1-5338

1-5310

1-5308

1-5316

Rotation.

- 1°

- 1° 25'

- 1°6'

1°30'

- 1° 20'

- 2° 30'

- 2°

- 0° 23'

- 0° 24'

- 0° 20'

- 0° 50'

- 0° 30'

- 1°

- 1° 30'

_ 1° 20'

Eugenol

(by Absorption).

82 per cent.

82 „

(^86) »
87
88
87
85
89
93
96
92
93 ,
92
91
94
An examination of the oil yielded by Zanzibar cloves from trees of
different ages, has been made by the chemists at the Imperial Institute l
with the following results :—
.No

1 2 3 4 5 6 7

8 to 9 years' old.

45

60

60 „^2

60 „

• '
  Stems from 1
  2

Yield.

17-8 °/ 0

19-2 (^7) O
18-8 °/ 0
17-4 (^7) O
6'5 °/ 0
5-9 7O
6-3 7O
Specific Gravity.

1-056

1-064

1-049

1-050

1-056

—

1-050

Rotation.

- 0° 23'

- 0° 30'

- 0° 29'

- 0° 37'

- 0° 33'

—

- 0° 42'

Bugenol.

89°/ 0

88 7.

84%

88 7.

90 7.

89°/ 0

(^1) Bull. Imp. lust., 12 (1914), 337. (^2) Tree in full flower.
From the mother-cloves (fruit).