370 THE CHEMISTEY OF ESSENTIAL OILS
mature trees than with plants grown from seed, although with the
seedlings the increase in height usually averages, for the first year
or two, from 6 ins. to a foot per month.
Eucalyptus Smithii is a well-defined species and has a somewhat
extensive range. The oil obtained by steam distillation is one of the
richest in cineol-content of all eucalyptus species so far examined. The
yield of oil is also good, as much as from 20 to 26 Ib. of oil being ob-
tainable commercially from the leaves and terminal branchlets which
can be packed in a 400 gallon tank. The oil consists very largely
of cineol, and the terpene is dextro-rotatory pinene. In commercial
samples the amount of high boiling constituents is often very small
indeed, the original distillation not being carried to the end, and 96
per cent, or more of crude commercially distilled oil may come over
below 190° C.
In addition to pinene and eucalyptol, the oil contains a phenol,
traces of aldehydes, d-eudesmol, butyl-butyrate (?), and a sesquiterpene.
A small quantity of a solid paraffin melting at 64° is also present.
The great importance of this oil from the commercial point of view
rendered an examination of samples obtained under different conditions
desirable, and the following samples have been examined by H. G.
Smith :—
(a) Leaves from lopped trees, seven months' growth; collected
May, 1913. (b) Leaves from lopped trees, fifteen months' growth ;
collected May, 1913. (c) Leaves from seedlings, twelve months'
growth ; collected June, 1914. (d) Leaves from seedlings two and a
half years' old; collected July, 1914. (e) Leaves from cultivated tree
at Marrickville; collected June, 1915. (/) Leaves from general
material, partly young; collected January, 1915. (g) Leaves from
general material collected three weeks later than (/). (h) Leaves
from old trees; collected March, 1913.
The constants, etc., given by the crude oils from the above material
were as follows :—
(a]
(b)
<«)(<*)
(«)
(ft(<7)
(h}Specific Gravity
at 15° C.0*9098
0-9157
0-9116
0-9139
0-9198
0-9156
0-9154
0-9210
Rotation.
aD.+ 7-6°
f 6-5°
+ 9-2°- 7-6°
- 4 7°
+ 5-3°
+ 5-1°+ 4-2°Refractive Solubility in
Index. 70 ° 0 Alcohol.1-4636
at 20°
1-4635
at 20°
1-4650
at 19°
1-4634
at 18°
1-4672
at 16°
1-4571
at 26°
1-4574
at 25°
1-4604
at 22°Required.
1-6 vols.1-2 „2-1 „1-4 „
1-2 „1-1 „1-1 „
1-1 „Saponification Eucalyptol
Number. per Cent.4-8
5-6
1-3
4-1
2-7
3-3
3-1
1-3
67-4
74-2
61-5
69-0
75-0
80-7
79-0
85-2
The eucalyptol was determined by the resorcinol method.