746 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [March 16, 1872. 
Citronella. 
The oxidized oil of which citronella is principally com¬ 
posed was submitted to analysis. It was purified by 
repeated fractional distillation till the boiling-point was 
nearly uniform. Combustions were made in the usual 
manner. 
I. Substance boiling at 202°-205° C. Specific gravity 
at 20° C., 0-8749. 0-4288 grm. gave 1*2230 grm. of car¬ 
bonic acid and 0-4215 grm. of water. 
II. Substance boiling at 199°-202° C. Specific gravity 
at 20° C., 0-8741. 0-396 grm. gave 1-1355 grm. of car¬ 
bonic acid and 0-386 grm. of water. 
These numbers indicate the composition C 10 H 16 O. 
Experiment. 
Calcu¬ 
lated. 
I. 
II. 
Carbon . 
Hydrogen .... 
Oxygen (loss) . . . 
77-78 
10- 92 
11- 30 
78-19 
10-83 
10-98 
78-94 
10-53 
10-53 
100-00 
100-00 
100-00 
This was verified by a determination of the vapour- 
density. 
Difference between weight of air and 
vapour.0-2912 grm. 
Temperature of balance case . . . 8° C. 
Temperature of sealing. 254° C. 
Capacity of globe.110-8 c.c. 
Residual air.0-6 c.c. 
Calculated density of vapour . . . 5-83. 
The theoretical density should be 5‘33, but there was 
a brown stain left in the globe. 
I propose naming this oil citronellol, in accordance 
with the usual plan of adopting -ol as the termination of 
the names of bodies of this nature. 
The oxygenized oil obtained from wormwood is said 
also to have the composition C 10 H ]n O, but its physical 
properties are very different, as will be seen by the sub¬ 
joined table, in which I have called it absinthol, to dis¬ 
tinguish it from the hydrocarbon. 
Oil. 
Specific 
gravity at 
20° C. 
Boiling 
point. 
Refractive 
Index A at 
20° C. 
Dispersion. 
Sensitive¬ 
ness. 
Specific 
refractive 
energy. 
; Circular 
polariza¬ 
tion.* 
Citronellol, Penang . 
0 8742 
200° 
1-4563 
0-0251 
50 
•5219 
,- 
Do. Ceylon . 
0.875 
200° 1-4594 
0-0262 
46 
•5251 
— 13 
Absinthol .... 
0-9267 
217° 
1-4543 
0-0243 
43 
•4903 
+ 134 
1 
The refraction equivalent of citronellol is, therefore, 
79-3 or 79-8, instead of the theoretical 73-7, as deduced 
from the composition C 10 H 16 O, while the equivalent of 
absinthol is only 74’5. The discrepancy in the case of 
citronellol is about the same as is found throughout the 
great phenyl group, as shown in my paper in the 
Journal of this Society (year 1870, p. 147), and if the 
two oils are really isomeric, it suggests an interesting 
difference in their molecular constitution. 
Cajeput . 
The oil of cajeput of commerce is said to be obtained 
from the leaves of Melaleuca Leucadendron , but the same 
oxidized compound was evidently the principal consti¬ 
tuent of the oils derived from the leaves of Melaleuca erici- 
folia and Melaleuca linarifolia , as well as of Euca lyptus 
oleosa , oils sent to this country from the colony of Victoria. 
This compound, though containing oxygen, may be 
distilled unchanged from metallic sodium. In this way 
* As in the previous paper, the circular polarization is 
given as actually measured in a tube ten inches long. It can, 
of course, be easily reduced to any scale that may be pre¬ 
ferred. 
the oils were freed from other oxidized products, and the 
specimens thus obtained exhibited the following phy¬ 
sical properties: — 
Oil. 
Specific 
gravity at 
20° C. 
Boiling- 
point. 
Refractive 
Index A at 
20° C. 
Dispersion. 
Sensitive¬ 
ness. 
Circular 
polariza¬ 
tion. 
Cajeput. 
0-9160 
174° 
1-4532 
•0213 
45 
— 2? 
Melaleuca ericifolia. 
0-8960 
173° 
1"4560 
•0239 
48 
+ 30 
Melaleuca linarifolia 
0-8985 
173° 
1-4651 
•0263 
46 
+ 11 
Eucalyptus oleosa . 
0-9075 
171°-176° 
1-4563 
•0227 
44 
+ 10 
The composition of cajeputol is well known to be 
C 10 H 18 O ; the refraction-equivalent of the specimen ex¬ 
amined was, therefore, 76-2, which accords with the theo¬ 
retical equivalent 76-3. 
Carvol and its Isomerides. 
In my previous paper it was stated that the oils of 
spearmint and nutmeg contain oxidized liquids, which 
appear to he isomerides of carvol, the principle which 
gives its peculiar flavour to the oil of caraway. They 
were named respectively menthol and myristicol. These 
have been submitted to a fuller investigation, and it has 
been found that oil of dill also yields a substance iso¬ 
meric, or perhaps identical, with ordinary carvol. 
There are two ways in which these oxidized oils may 
be separated,—either by fractional distillation, which 
must always be an imperfect method, or by taking ad¬ 
vantage of the fact that they form crystalline bodies 
with hydrosulphuric acid, which can be easily purified, 
and which yield the original oil when decomposed by an 
alkali. The oil from nutmeg, however, was not to form 
such a compound. 
The following are the physical properties of the sub¬ 
stances above mentioned. Menthol I. was prepared by 
fractional distillation. Menthol II. was prepared from 
the hydrosulphuric compound. 
Substance. 
I Boiling- 
point. 
Specific 
gravity at 
20° C. 
Refractive 
Index A at 
20° C. 
| 
Dispersion. 
►Sensitive¬ 
ness. 
Refraction 
equivalent. 
Circular 
polariza¬ 
tion. 
Carvol . . • 
227° 
0-9530 
1-4886 
0-0345 
46 
51-26 
+ 145° 
Dill carvol . • 
— 
0-9562 
1-4891 
0-0333 
45 
51-15 
+ 108° 
Menthol I. . * 
225° 
0-9515 
1-4839 
0-0326 
44 
50-86 
— 103° 
Menthol II.. * 
225° 
0-9394 
1-4791 
0-0311 
42 
51-01 
— 114° 
Myristicol . * 
224° 
0-9166 
1-4848 
0-0312 
46 
51-21 
+ 31° 
Dill Carvol. —The oxidized oil obtained from dill has 
the same odour as that from caraway, an odour which 
can scarcely be confounded with any other. Like carvol 
also it forms a crystalline compound when treated with 
sulphide of ammonium in alcohol. 0*527 grm. of these 
crystals oxidized by strong nitric acid, and treated with 
barium salt, gave 0-360 grm. of sulphate of barium. 
This result agrees with what should be obtained from 
the known hydrosulphate of carvol (C 10 H 14 O) 2 H 2 S. 
Carbon 
Calculated. 
. . . 71-86 
Found. 
Hydrogen 
. . . 8-98 
— 
Oxygen . 
. . . 9-58 
— 
Sulphur . 
. . . 9-58 
9-37 
100-00 
- 
I am disposed, therefore, to regard this compound 
derived from dill as identical rather than isomeric with 
carvol. 
Menthol. —This compound has the very characteristic 
odour of spearmint, totally different from that of carvol, 
and it retains the same odour when it has been repro¬ 
duced from the hydrosulphate. 
A combustion was made. 0-3945 grm. yielded 1-159 
carbonic acid, and 0-3415. This agrees with the for¬ 
mula C l 0 H 14 O. 
