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The price moves with that of lemongrass oil. There is no other 
raw material of equal richness. When citral is kept, either in the 
pure state or in the form of a mixture, it should be protected from 
heat and sunlight. 
Coumarin. Since the price has gradually been ruined by new 
competitors who have decidedly overestimated the consumption, all 
interest in this article appears to have died away. When judging the 
prices, the quality of the various products, which are not by any means 
all equal, should be taken into consideration. Our coumarin has reached 
the highest degree of perfection by repeated recrystallisation. 
It is a well-known fact that many chemical bodies undergo changes 
by the action of light, and especially of direct sunlight. In the case 
of colourless organic bodies or solutions thereof, this can frequently 
be observed by the occurrence of a more or less strong yellow color- 
ation. The examinations of Ciamician and Silber^) have shown 
that coumarin is also subject to such changes. Both crystallised 
coumarin, and also that in alcoholic solution, are polymerised in 
sunlight in the course of a few weeks into hydrodicoumarin (melting 
point 262°), with yellow colouration. As this body dissolves with dif- 
ficulty in alcohol, it separates out in crystalline form from the coumarin 
solutions. The formation of this odourless substance causes a continuous 
decrease of the aroma. 
For this reason it does not appear advisable to keep coumarin or 
its solutions for a prolonged time exposed to the light; under all 
circumstances a cool, dark place should be much preferred. 
With regard to similar occurrences in heliotropin, further details 
will be found under that heading. 
Eucalyptol. The slight difference in price between the crude 
oil of the globulus species and pure eucalyptol has, as we foresaw, 
brought about a great demand for the latter, so much so, that the 
execution of large orders was now and then somewhat delayed. 
This crisis, however, has passed, since new installations for the 
manufacture have been brought into operation. 
Eugenol. The value moves up and down with that of clove 
oil, and everything said about the latter applies to the former. The 
demand was brisk, corresponding to the advancing market. 
Geraniol. The use of this product, which we were the first to intro- 
duce into commerce, has in the course of time grown to large dimensions. 
Geraniol plays an important part in nature. It forms a constituent of 
^) Berliner Berichte 36 (1903), 4266, and 35 (1902), 4130. 
