that they were just only sufficient for the determination of specific gravity and rotation. 
These values were within the recognized limits of sweet orange oil: — 
Oil from green oranges: dis0 0,8515; @p»0 + 98° 2’ 
” ” yellow ” > dis0 0,8492; Ap 200 + 97° 22’, 
SCIENTIFIC NOTES ON ESSENTIAL OILS. Ze 
Eucalyptus Oil. Part 10 of the second volume, and part 1 of the third volume 
of J. H. Maiden’s work: A critical revision of the genus Eucalyptus (Sydney 1914) 
contain descriptions of the following species of Eucalyptus: E. gigantea, Hook. f. 
(Z. delegatensis, R. T. Baker; H. obliqua, L’Hérit. var. alpina, Maiden); E. longifolia, Link 
et Otto (EZ. Woollsii, F. v. M.); E. diversicolor, F. v. M. (E. colossea, F. v. M.); H. Guilfoylei, 
Maiden; E. patens, Benth.; E. Todtiana, F.v. M.; EH. micranthera, F.v. M.; E. cinerea, F.v. M. 
(EZ. pulverulenta, F. v. M. non Sims.; HE. Stwartiana secunda, F. v. M.; E. pulverulenta, 
F. v. M. var. lanceolata, Howitt; EH. Stuartiana, F. v. M. var. cordata, Baker et Smith); 
E. ¢. var. multiflora and nova anglica (nov. var.); EH. pulverulenta, Sims. (E. pulvigera, 
A. Cunn.; LE. rigida, Hoffmg.; EH. cordata, Loddiges non Labill.); EH. cosmophylla, F. v. M. 
and EF. gomphocephala, A. P. DC. 
Fennel Oil. The use of this oil against vermin is referred to in a short note 
on page 74. : 
Galangal Oil. In the course of an examination of galangal oil, E. Fromm and 
H. Fluck*) obtained a fraction of b. p.171 to 173° containing cineol. When shaken 
with aqueous concentrated hydriodic acid, fairly stable, dark green crystals of an 
iodine combination were formed. From cineol (eucalyptol) the same green body was 
obtained in like manner. A closer examination revealed the fact that this combination 
is formed only if the hydriodic acid contains free iodine. If it is freed from iodine 
by shaking with red phosphorus, cineol is converted to dipentene di-iodide, which had 
been prepared by Wallach and Brass by subjecting well-cooled cineol to the influence 
of gaseous hydriodic acid. Inasmuch as the dark green iodine combination of cineol 
is obtained neither with free hydriodic acid nor with pure iodine solution, it is evident 
that both substances are necessary for its formation. As a matter of fact cineol forms 
these green crystals instantaneously with acidulated iodine and iodide of potassium 
solution. This reaction offers so little difficulty that it is even possible to titrate 
cineol in this manner. To this end 0,2155 g. of cineol are well shaken with 20 cc. 
of a solution of one-tenth-normal iodine in potassium iodide and a sufficiency of dilute 
hydrochloric acid, in which process the cristallized combination separates readily. 
After filtering and washing with cold water, the unused iodine in the filtrate is titrated 
back with a one-tenth-normal thiosulfate solution, for which purpose 6,55 cc. were 
required. Therefore 0,2155 g. of cineol used up 13,45 cc. of one-tenth-normal iodine- 
iodide of potassium solution, or 1 gram molecule cineol 960 cc. normal iodine solution. 
It follows that the cineol used was of 96 p.c. strength, and that 1 molecule of cineol 
binds 1 atom of iodine. It is suggested that by this method the amount of cineol in 
fractions containing more than 60 p.c. of cineol may be determined with certainty. As 
we have convinced ourselves by experiments, and as was to be expected, it fails 
whenever, besides cineol, other combinations, such as f.i. terpenes, are present, which 
1) Liebigs Annalen 405 (1914), 175, 181. 
