Chemistry of Essential Oils

234 THE CHEMISTKY OF ESSENTIAL OILS.

Specific gravity

Optical rotation

Refractive index

Menthol as esters

Total menthol

0-898 to 0-915 (rarely to 0'930>

• 23° to - 37°
  1-4580 „ 1-4680
  2*8 to 20-8 per cent.
  48 „ 81

It is soluble in 3 to 5 volumes of 70 per cent, alcohol.

DALMATIAN PEPPERMINT OIL.

French peppermint plants cultivated at Trieste yield an oil of good
aroma, which has been examined by Schimmel & Co.^1 The crude and
rectified oils had the following characters :—

Specific gravity

Optical rotation

Refractive index

Menthol as esters

Total menthol

Crude Oil.

0-907 to 0-913

Rectified Oil.

0-909 to 0-914

• 15° 45' „ - 20° 58' - 11° 45' „ - 18° 12'
  1-4623 ,, 1-4668 1-4604 „ 1-4678
  3-4 to 4-8 per cent. 2-6 to 3-8 per cent.
  46-3 „ 54-2 „ 39-6 „ 54-1

The oil is soluble in 3 to 4 volumes of 70 per cent, alcohol.

HUNGARIAN PEPPERMINT OIL.

Irk^2 has described the oil of peppermint distilled in Hungary, and
which resembles American oil in aroma. The dry plants yielded 1*17
per cent, of oil, having the following characters:—

Specific gravity

Optical rotation

Refractive index

Menthol as esters.

Total menthol

Menthone

0-9014 to 0-9192

• 26° „ - 32-4°
  1-4632 „ 1-4769
  8 to 12-8 per cent.
  56-4 „ 65-2 „
  7-4 „ 13-2
  It is soluble in 2 to 5 volumes of 70 per cent, alcohol.
  An interesting series of experiments on the value of manuring has
  been carried out on Hungarian peppermint plants.^3 These experiments
  are summarised in the following table :—

Artificial Manure.

None /

With Sodium Nitrate. |

With Sodium Nitrate and

Superphosphate.

With Sodium Nitrate, Super-

phosphate and Kainit

Marshy ground at Admont

without manure

Farmyard

Manure.

Without

With

Without

With

Without

With

Without

With

Fresh

Herb

(kilos per

hectare).

4-240

6*760

6-640

10-560

7-120

8-980

8-780

13-080

7-89

Dried

Herb

•(kilos per

hectare).

1-300

2-000

1-860

2-820

1-940

2-320

2-200

3-140

2-83

nil

(per

Cent.).

0-77

0-88

0-74

0-81

0-73

0-84

0-72

0-93

0-62

Weight of

Oil

(kilos per

hectare).

10-01

16-40

18-76

22-84

14-16

19-94

15-84

29-83

17-55

It will thus be seen that the yield of oil from a given area of com-

pletely manured soil was nearly double that from the same area which

(^1) Bericht, October, 1911, 69. (^2) Kistrlettigyi Kozlemdnyek, 13 (1910), 8.

• Plwrm. Post (1912), 2.