300 THE CHEMISTEY OF ESSENTIAL OILS
found wild in other tropical and subtropical countries, yields an essential
oil having the following characters :—
Specific gravity 0*966 to 0*981
Optical rotation + 3° „ + 6°
Refractive index 1-5090
According to Semmler,^1 the oil contains a sesquiterpene, and the di-
methyl ether of thymohydroquinone. Traces of coumarin are also
present.
OLLS OF SOLIDAGO.Various species of Solidago yield essential oils, of which the best
known is the " golden rod oil," which is obtained to the extent of about
1 per cent, from Solidago odora, a plant very common in the United
States, east of the Eocky Mountains. The oil has the following
characters:—
Specific gravity 0-937 to0-960
Optical rotation + 7° „ + 14°
Refractive index 1-5050 „ 1-5160
Ester value 6 „ 10
,, ,, (after acetylation) 18 „ 25
According to Miller and Moseley,
2
the oil contains about 76 per cent,
of methyl-chavicol. Traces of pinene are possibly present, but this is
doubtful. Borneol is present in small quantity.
Canadian golden rod oil is obtained from Solidago canadensis. It is
a, yellow oil of aromatic odour, of specific gravity 0
*
859 and optical rota-
tion - 11° 10'. It consists of about 85 per cent, of terpenes, of which
pinene, phellandrene, dipentene, and probably limonene are the con-
stituents. There are also present borneol, bornyl acetate, and cadinene.
Solidago nemoralis is a plant which grows from Quebec to the North-
West Territory, south to Florida and west to Texas and Arizona. A
sample of the oil obtained from this species was examined by Schimmel
& Co.
3
It was bright olive-green in colour, and had a peculiar odour,
reminding somewhat of cypress oil. It had a specific gravity 0'8799,
optical rotation - 23° 10', ester number 14'4, ester number after acety-
lation 38*2, and formed a cloudy solution in about seven or more volumes
of 95 per cent, alcohol.
An average of ten samples examined by Miller and Eskew
4
had the
.following characters :—Specific gravity -^ 00»858 2*>°
Optical rotation - 16° 17'
Refractive index 1*4739
Saponification value 5*6
„ „ (after acetylation) .... 9-4
It is soluble in about 4 volumes of 90 per cent, alcohol, and in about
24 volumes of 70 per cent, alcohol. On fractionation the oil yielded
/?-pinene and traces of salicylic and acetic acids. The presence of
borneol was considered probable, but no definite proof was obtained.
Phellandrene was not present, and no reactions were obtained for
aldehydes or ketones, phenols or camphor. The chief constituent is
pinene, a mixture of the dextro- and laevo-rotatory varieties.(^1) Berichte, 41 (1908), 509. 2 Schimmel's Report, April, 1906, 63.
9Ibid. 4Jour. Amer. Chem. Soc. (1914), 2538.