198 ODOROGRAPHIA. 
darker and brownish. Cinnamon oil of fine quality when brought 
into contact with the tongue should produce a taste of intense 
sweetness, far exceeding the sweetness of sugar: with an inferior 
quality a clove-like taste is first developed, and after a time a 
slight sweetness,—such an oil has no higher value than cassia oil. 
Cinnamon oil and cassia oil are said to be of thej same chemical 
composition, the marketable value of both being estimated by the 
amount of cinnamaldehyde contained in them ; methods of esti- 
mating this are also given under the article “ Cassia.” 
As before remarked, the principal constituent of oil of cinnamon 
is cinnamaldehyde, it also contains a hydrocarbon which has not 
been thoroughly investigated. These may be separated by 
bringing the oil into contact with concentrated nitric acid; the 
erystals which separate out in long oblique rhombic prisms or 
small plates are then decomposed by water into nitric acid and | 
the free aldehyde. Cinnamaldehyde may also be obtained pure 
by agitating oil of cinnamon with 3 or 4 volumes of a concentrated 
solution of acid potassium sulphite ; the compound, which separates 
im scales, is dried, washed in alcohol, again dried, and finally de- 
composed with dilute sulphuric acid*. According to Peine t 
an alcoholic solution of 50 parts of oil of cinnamon is agitated 
with 90 parts of a 50-per-cent. solution of sodium sulphite, and 
the compound, after washing with alcohol, decomposed with 
sulphuric acid ; 40 cubic centimetres of this, diluted with an equal 
volume of water, being employed for every 100 c. ec. of the sulphite 
solution. The aldehyde is then distilled with steam, the distillate 
extracted with ether, and after the evaporation of the ether, frac- 
tionated under diminished pressure. 
Cinnamaldehyde is a colourless, very pleasant smelling liquid, 
which decomposes on distillation at the ordinary pressure, but 
boils without alteration at 130° under a pressure of 30-40 mm. 
Cinnamaldehyde may be very easily prepared synthetically by 
allowing a mixture of 10 parts of benzaldehyde, 15 parts of 
acetaldehyde, 900 parts of water, and 10 parts of a 10-per-cent. 
solution of caustic soda to stand for 8 or 10 days at a temperature 
of 30°, the whole being frequently agitated and finally extracted 
* Ann, Chem. Pharm. lxxxy, p. 271. 
T Ber. Deutsch. chem. Ges. xvii. p. 2109. 
