256 ODOROGRAPHIA. 
leaves room for doubt ; for in what manner can it be determined 
that “1000 parts of balsam are neutralized by 75 parts of sodium 
carbonate”? The execution of this experiment is not quite so 
simple as it would appear in this laconic requirement. Should the 
balsam be boiled with the finely-powdered carbonate, the action of 
the same aided by means of water, or must, inversely, the balsam be 
diluted with alcohol? Good Peru balsam was boiled for a day with 
an excess of sodium carbonate and 10 times its weight of alcohol 
(sp. gr. 0°830) in a flask provided with an inverted condenser ; 
91:6 parts of sodium carbonate were required for 1000 parts of 
balsam. It is probable that hereby, finally, not only the free acid 
is combined with the sodium, but also that a decomposition of the 
cinnamic ether or cinnamein begins. It appears therefore more 
advisable to extract the free cmnamic acid by means of lime, in that 
it may be accepted that the latter is without action on the compound 
cinnamic ether. If, for example, 50 parts of balsam are boiled for 
two hours with a mixture consisting of 20 parts of lime and 500 
parts of water, the evaporated water restored, the boiling mixture 
filtered, and the mass twice washed, employing each time 200 parts 
of hot water, the cinnamate of calcium is thus obtained in solution. 
This is evaporated to 200 parts (whereby it becomes more and 
more of a yellowish colour, developmg a coumarin odour, which 
resembles the odour of the Balsam Peru pods), and, after super- 
saturation with hydrochloric acid, is placed for some hours in the 
cold, whereupon the separated cinnamic acid is collected, after 
draining pressed between bibulous paper, first dried by exposure 
to the air and finally on the water-bath. When prepared from 
pure balsam the acid consists of loose, not smeary, somewhat 
brownish crystals, the weight of which amounts from 2 to 4 per 
cent. Adulterated balsams yield, according to the nature of the 
admixture, a much less pure cinnamic acid, or they give much 
more or less than 3 to 4 per cent. of acid. That cinnamic acid is 
obtained is manifest from the fact that it requires for solution 
100 parts of boiling water, while benzoic acid dissolves at 100° C. 
in 15 parts of water. Upon cooling the hot, saturated, aqueous 
solution, the cinnamic acid is, for the most part, again separated. 
If 2 parts of the crystals, purified in this manner, are shaken 
in a flask with 1 part of potassium permanganate and 20 parts of 
luke-warm water, a strong odour of bitter-almond oil is developed, 
the cinnamic acid yielding benzaldehyde. 
