~ > RE Ah Ps 
20 REPORT OF SCHIMMEL & Co. OCTOBER 1915. 
mentioned cineol, in melting point and specific gravity, with the requirements of the 
American Pharmacopoeia, that it contains no other parts of eucalyptus oil any more. 
This, however, is a slight error, seeing that from the melting point‘) as well as 
from the optical behaviour it can be seen that even the cineol regenerated from 
the arsenic acid compound is impure, although it has to be admitted that the 
impurities of the cineol originating from the resorcinol compound are a little more 
pronounced, as it has a still lower melting point. But in both instances the impurity 
is, comparatively speaking, trifling and does not permit of any conclusions being drawn 
as to how far the correctness of the results obtained in the cineol determination are 
influenced thereby, the less so as in the case of these cineols we have to deal with 
collective products from several determinations. The only correct course would have 
been to publish the ysesults themselves. 
From our own experiments, carried out with oils as well as with mixtures made 
in our laboratories, it is evident beyond doubt that resorcinol yields at least as good 
results as arsenic acid. We have worked on the one hand according to the modified 
resorcinol method, but on the other hand we also separated cineol as a solid resor- 
cinol compound. When dealing with mixtures we did not confine ourselves merely to 
the most favourable cases, by simply mixing cineol with a terpene, but in two cases 
we added terpineol, i.e. an alcoholic constituent which has often to be reckoned with 
in oils to be tested, and by which the results are unfavourably affected. Consequently 
mixtures of this nature form a far better standard valuation for checking a certain 
method, than if cineol be merely diluted with a terpene. In the following table we 
have collected the results of our experiments. 
Arsenic acid method Resorcinol method 
No. bation of aaa Gs caro seeomposing the 
petroleum petroleum fraction cineol=resarcinul 
La a ether ether 170 to 190° | compound 
{Limonene |... Sap, |p 787% | One| lea 
{| timonene oe ee 
[i peat ee ae 
3 Limonene : 04 1 .->. GaeaZon);, 13 pic. eer D2 pyres Ain 
| Terpineol. - .-.2 co. cehee eas 3; | 
| Limonene © 22S 9 | 
4, limonene . 73°27. Sse: ee Do, 62°%; bo arr 
| Terpineol . 10K; | 
5. | Eucalyptus oil, Globulus oaks 70’ p: Cc. 82°, Oh 55 oo ws 
6. Cavput 700 5 ee eee see as 535, C348 OT me 
Several points may be gathered from the figures obtained by us. To begin with, 
it is shown that, when testing with arsenic acid, the use of petroleum ether is 
inadvisable, seeing that even with a high cineol content the values obtained are too low, 
1) Pure eucalyptol melts between +1 and +1.5° (comp. Report October 1907, 49); the indication of | 
the U. S. P. is not correct. 
