THE ODOUR OF ROSE. Bh 
of lemon, has been studied by Semmler*, and is believed to be 
identical with the aldehyde obtained by the oxidation of geraniol. 
The nature of stereoptene was studied by Fluckiger + in 1869, 
and by Gladstone in 1872 f. 
Recent experiments made by Schimmel & Co., of Leipzig, showed 
that by digesting stereoptene at a temperature near to its melting- 
point, it was possible to obtain, by crystallizing, fractions of 
different melting-points, and by repeatediy putting the substance 
through these operations, two constituents were finally obtained, 
one of which melted at 41° C. and the other at 22°C. The result 
of this experiment on Turkish stereoptene was confirmed by re- 
peating it on stereoptene of known purity resulting from the dis- 
tillation of roses grown by themselves. These investigations tend 
to prove that, contrary to the views hitherto held, stereoptene is 
not a simple body, but a mixture of two or more homologous 
hydrocarbons. 
A drop of stereoptene let fall on paper is not dissipated by the 
heat of a stove, even after several days. When it is carefully 
melted at the temperature of sun-heat and then allowed to cool, it 
sets in microscopic crystals of a peculiar form, most of them being 
truncated hexagonal pyramids, which, nevertheless, do not belong 
to the rhomboidal system, as their angles are manifestly unequal ; 
many of them are curved into the form of an 8 or §. Examined 
under the microscope by polarized light, they present, by reason 
of their refractive power, a very brilliant aspect. Stereoptene is 
a very stable, unalterable body, but on boiling it for several days 
in fuming nitric acid it slowly dissolves and decomposes into 
various acids, homologues of the fatty acids, and possibly also 
fumaric acid. Amongst the former, butyric and valerianic acids 
are recognizable ; the principal product, however, is succinic acid, 
which was found in pure crystals, giving the well-known reactions. 
According to experiments of the same observers, there are many 
points of resemblance in the physical characteristics of stereoptene 
and paraffin. 
Besides the crystallizing test, which is applied to estimate the 
purity of otto of rose, it is necessary to examine the manner of 
crystallization in order to ascertain if that crystallization be caused 
* Bericht d. Deutsch. chem. Ges, xxili. p, 3556, and xxiy. p. 203 (1891). 
+ Pharm. Journ. [2] x. p. 147. t Journ. Ch. Soc. x. p. 12. 
