Chemistry of Essential Oils

232 THE CHEMISTRY OF ESSENTIAL OILS

Specific gravity.

Optical rotation.

Refractive index.

Menthol as esters

Total menthol.

Menthone.

0-900 to 0-920

• 12° „ - 26°
  1-4620 „ 1-4645
  8 to 29 per cent.
  40 „ 70
  12 „ 18

Umney and Bennett found the oil distilled from July-cut plants to

contain only about 40 per cent, of menthol, whilst oil from the later

FIG. 30.—Distillation of peppermint in Piedmont.

Carles ] [Parfumerie Moderne.

second cutting contained 7O5 per cent. But no generalisation is pos-
sible without the examination of a number of samples.

EUSSIAN PEPPERMINT OIL.

A certain amount of peppermint oil is distilled in various parts of

Russia, most of which is used in the country itself; but it has recently

appeared on the English market, where its reception has been favourable.

It is distilled in Tambow, the Caucasus, Poltava, and the Ukraine. The

dried herb yields about 1*5 to 1*7 per cent, of oil.

Maisit

1

states that peppermint oil is distilled in various parts of

European Eussia, generally in very primitive stills, with the result that

the oil is often burnt and of poor odour. During the past few years

peppermint plantations have been laid out in the Caucasus districts,

which, owing to favourable climatic and soil conditions, are very suitable

for the cultivation of numerous medicinal plants.

A yield of from T6 to 1*7 per cent, on the dried leaves and flowers

is the average obtained. Maisit has examined the oil distilled from one

year old and two year old plants. Both are pale yellow7 in colour,

not very soluble in 70 per cent, alcohol, and having the following

characters:—

' Ar ch, der Phaim , 249 (1911), 637.