68 REPORT OF SCHIMMEL & Co. OcTOBER ‘O14 Aree 1915. 
a 20 
On page 42 of this Report, a booklet on Shi-Gyu and Yu-Ju oils, oublishen bi 
K. Nagai with many illustrations and maps, has been discussed. 
O. Simon’), in an article on the principles of obtaining essential oils by distillation, 
and on steam distillation generally, gives a short description of the distilling apparatus, 
the preparation of the raw materials and the various ways of distilling, ending up 
with some remarks on the theory of distillation. 
O. Volz’), in an article well worth reading, describes the development of the 
industry of scents and aromatics in a very concise form. After a short historical 
introduction, he deals with the production of essential oils from plants by steam 
distillation, the manufacture of synthetic aromatics, of scents and, finally, of toilet soaps. 
Analytical Notes. 
Change of density and of index of refraction of essential oils according to the 
temperature. 
As ascertained by experiments, carried out in our laboratories some years back’), 
the density of a number of essential oils changes in comparison with water of 15° 
by about 0,00075 for every degree centigrade. On account of observations, made 
with about 45 different essential oils, K. Irk*) indicates the modifications of the 
specific gravity for 1° centigrade as follows: between d¥> and d%> 0,0008; between 
d= and d22 0,0007; between d2 and dvs 0,0006; in round figures. 
For numerous essential oils, K. Irk®) (iRenise determined the ae which the 
index of refraction underwent according to temperature. It amounts for 1° centigrade: 
between 15 and 20° to 0,00043 in the mean; between 10 and 15° to 0,00043; between 
20 and 30° to 0,00045 and between 10 and 30° to 0,00044,; i.e. on an average 0,00044. 
His observations, made with 50 different oils, are given in the form of tables. 
We observed at the time a change of 0,00035 on an average for every degree of 
temperature’). 
Estimation of esters in volatile oils. | 
When estimating esters in volatile oils under apparently equal conditions, results | 
are obtained sometimes which do not tally. According to A. Béhal’s’) indications, 
the differences come up to 3 p.c. The same observations are made when one tries 
to determine the composition of a formate or acetate. The author sees the cause of 
these differences in that during the saponification esters are formed intermediately, 
which boil very low perhaps and may thus escape through the condenser. As he 
ascertained experimentally, the esters are decomposed by potash lye in the presence 
of an alcohol, when a certain quantity of the ester of the alcohol of the lowest 
molecular weight is formed and the alcohol of the highest molecular weight split off. 
When heating for instance cocaine, or the benzoates of phenol, p-chlorophenol, m-cresol, 
creosol, eugenol, &c. with alcoholic half normal potash lye, a certain quantity of ethyl 
ay Seifenfabrikant 34 (1914), 1299, 1318. — *) Der Siegeslauf der Technik. Edited by M. Geitel. II. ed., 
p. 353. From a reprint kindly sent us. — +*) Report October 1905, 87. — +4) Pharm. Zentraih. 55 (1914), 831. — 
5) Ibidem 789. — %) Gildemeister and Hoffmann, The Volatile Oils, 2"4 ed., vol. I, p. 561. — ‘%) Bull. Soc. 
chim. IV. 15 (1914), 565. : 
