. SCIENTIFIC NOTES ON ESSENTIAL OILS. 21 
solution is prepared with 50 p.c. alcohol, whereas with oils 1 g. is dissolved in enough 
of 85 p.c. alcohol to produce a total volume of 40 cc. The solution must be well 
filtered. Exactly 2 cc. are used for analysis in both instances, same as with the citral 
solution. The colorimeter used in these tests is a modification of the one designed 
by Schreiner. For further particulars concerning its construction we refer to the 
original treatise which contains an illustration of the apparatus. 
According to this process, Little found from 3,14 to 4,68 p.c. of citral in lemon oils. 
According to J. W. Marden and V. Elliott’), the best way to obtain citral from 
lemon oil is to extract 1 vol. of the oil with 18 volumes of 50 p.c. alcohol. In this 
manner an oil showing a citral percentage of 3,61 p.c. yielded 90 p.c. If 45 p.c. 
alcohol is used, the result is less favourable. As regards the theoretical reasonings 
which led the authors to this method (application of the distribution coefficient) we 
must refer readers to the original paper. 
The authors do not state the method by which the citral percentage of lemon oil 
was determined. 
Mandarin Oil, Japanese. From Japan we received, early last year, three samples 
of mandarin oil of Japanese origin, which are reported upon below. As they were 
colourless, it was evident that these oils had not been obtained by pressure, as is 
the custom in Italy, but by distillation. Consequently they were devoid of the fine 
aroma of the Italian oils, but smelled chiefly of limonene and cannot, therefore, 
compete with genuine mandarin oils. The different method of production is also 
illustrated by the chemical constants, as specified in the table below: — 
Gp of the first 10 p.c. solubility 
diso ap of the distillate acid v. ester v. in 90 p.c. alcohol 
I. 0,8489; -+92°35’; + 91°32’; 03; 3,7; 5,5 vol. and more 
Pee ee to” 0 00 10). 03. 36; 85D yn fw 
Ill, 00,8541; -+ 68°57’; pO A MEO A Oe yar ta 
Three oils sent us under the name of Mikan oil were evidently also mandarin oils, 
for the mandarin fruit is called “Mikan’’?) in Japan. These oils showed somewhat 
similar constants to the above-mentioned distillates: — 
diso 0,8483; a + 92°20’; soluble in 6 volumes and more of 90 p.c. alcohol 
diso 0,8478; 2p == 90° 56 + ” ” 6,2 ” ” 7 ” 90 ” ” 
diso 0,849; ay 35 90° 35 G ” ” abt. 10 ” ” ” ” 90 oan ” 
The values of Italian mandarin oil are within the following figures: diso 0,854 to 
0,859; a) -+-65to + 75°; 4p of the first 10 p.c. of the distillate very little lower, or 
even up to 2° higher than the original oil; acid v. up to.1,7; ester v. 5 to 11; more 
or less turbidity when dissolved in 7 to 10 volumes of 90 p.c. alcohol. 
An English journal*) also reports on a mandarin oil of Japanese origin. This oil 
too had been obtained by distillation and according to our contemporary it was of a very 
fine odour; it showed a specific gravity of 0,848 and a rotation of +-94°. A slight 
fluorescence noticed in this oil is put down by the author to the presence of methyl 
ester of anthranilic acid. We may: *De> permitted to point out that, according to 
7 4 & 
21.3 » 2 
*) Journ. Ind. Eng. Chemistry 6 (1914), 930. — 2%) J.J. Rein, Japan nach Reisen und Studien, vol. Il, p. 105, 
Leipzig 1886. — *) Perfum. Record 5 (1914), 72. 
