LABIATE 205
stages. Specific gravity and rotation therefore become less, whilst
alcohol content and solubility increase ; inasmuch as the borneol greatly
preponderating in the " Ardeche " type is gradually substituted towards
the " Var " type by linalool and geraniol. The laevo-rotation of the last-
mentioned oil is also remarkable, but Birckenstock considers that up to- 1° 10' this is still normal, provided that the first 10 per cent, of the
distillate rotate to the right.
Our knowledge of the chemistry of this oil is chiefly due to*
Bouchardat,
1
who showed that it contained pinene and cineol (euca-
lyptol). Later, he proved the presence of camphor, linalol, borneol, and
camphene. Terpineol and geraniol are also present in small quantities.
Probably a sesquiterpene also exists in this oil, but its presence has not
yet been definitely proved. The similarity of the odour of this oil to
true lavender and rosemary is easily explained when one considers that
FIG. 24.
the chief ingredients of the oil are cineol, borneol, linalol, and camphor.,
Linalol is an important ingredient of lavender oil, whereas cineol,
borneol, and camphor oil are all present in rosemary oil.
Spike oil is largely alterated with turpentine, and probably, ac-
cording to Umney, with the commoner varieties of rosemary oil. The
former is detected by the adulteration in specific gravity and solubility,,
whilst the latter interferes with the solubility and the percentage of free
alcohols present. Spike oil is largely used in cheap perfumery and in
the manufacture of certain kinds of lacquer for fine china manufacture.
It is also largely employed as an adulterant of ordinary oil of lavender.
EOSBMABY OIL.This oil is distilled from the flowering tops of the plant Rosmarinm
officinalis, a native of the south of Europe. The rosemary is a plant,
(^1) Comptes Rendus, 106 (1888), 551; 117 (1893), 53 and 1094.