202 THE CHBMISTEY OF ESSENTIAL OILS
Those samples in which very high ester values had developed were
of such acid and disagreeable odour as to be unfit for use. These ob-
servations are confirmed by the following analyses by Passmore, the
original analysis being made on comparatively freshly distilled oils, and
the second analysis after a period of several years on the same oil:—
Al/03.Al/04.M/05.
LM/08.LM/09.Acidity
Ester Value
Acidity
Ester Value
Acidity
Ester Value
Acidity
Ester Value
Acidity
Ester ValueOriginal
Analysis.nil
11-0 per cent.
nil
8-8 per cent.
nil
7*5 per cent.
nil
8*7 percent.
nil
8'8 per cent.Second Analysis
(1912).nil
11*0 per cent.
2-00 ,
21-2 ,
1-31 ,
17-7
2-29 ,
22-7
2-68 ,
20 2The Constituents of Lavender Oil.—The earliest systematic investiga-
tion of this oil was that of Proust and Dumas,^1 who found a camphor
(lauro-camphor) present. There is little doubt, however, that the oil
they examined was not a genuine lavender oil, but contained other oils,,
possibly including spike oil.
Bertram and Walbaum^2 found that linalyl acetate was the principal
constituent of French lavender oil, and that linalol was also present in
the form of esters of butyric, valerianic, and caproic acids. A small
amount of free linalol is also present in the oil.
Semmler and Tiemann^3 have isolated limonene and a sesquiterpene
from the oil. This sesquiterpene has later been identified as caryophyl-
lene. Very small amounts of a-pinene are present, as well as a small
quantity of geraniol, probably in the form of esters.
Cumarin is present, in traces only, and furfurol, an aldehyde which
is probably valeric aldehyde, amyl alcohol, ethyl-n-amyl-ketone, and
d-borneol are all constituents of the oil, but in very small amount.
According to Elze4 nerol and thymol are present in lavender oil,
but Schimmel & Co. deny that thymol is a constituent of the pure oil,
and consider that Elze was working on an adulterated specimen.
Traces of cineol may be present, but this is doubtful.
The principal difference between English and French oil of lavender
is that the former contains only a very small quantity of linalyl esters;
whilst cineol appears to be a normal constituent of English oil. Semm-
ler and Tiemann
5
have isolated from English oil the terpene limo-
nene, linalol, and Z-linalyl acetate. Cineol and a sesquiterpene are also
normal constituents of the oil.
OIL OF LAVANDULA DENTATA.
This oil is not commercially distilled from the unmixed herb, but
there is no doubt that the flowers are to some extent gathered promiscu-
ously and distilled with other lavender species in Spain—and to a smaller
extent in France.
lAnnalen 6 (1833), 248.
* Bericht, xxv., 1880.(^8) Bericht, 25 (1892), 1186.
(^2) Jour, prakt. Chem., 11, 45 (1892), 590.
4
Chem. Zeit., 34 (1910), 1029.