— 28 — 
following table which contains some of the results obtained by us, 
may serve as an illustration of the foregoing: 
Eugenol 
S-Ccording to XJ m n 6 y 
(5 per cent. NaOH) 
-content 
Verley and Bolsing 
Mixture 
with 
lo per cent, eugenol 
9,5 per cent. 

13,2 per cent. 
?? 
55 
49,5 - 55 
5I533 55 55 
55 
75 '5 55 5> 
755O „ „ 
73,58 5, 55 
Pure eu 
^enol 
100,0 „ ,, 
102,3 „ 
English 
oil of 
cloves 
9O55 5, „ 
79,94 » 
55 15 
55 ..... 
735O „ „ 
74,12 „ „ 
? ? 
55 15 
80,0 „ 
69,53 55 
These few examples may already suffice to justify our unfavourable 
opinion on the method proposed by Verley and Bolsing. It is all 
the more surprising that we have not arrived at approximately as 
satisfactory results as Verley and Bolsing, as they used normal 
liquor for titration, but we only semi-normal solution. Further, it is 
not quite clear on what grounds Verley and Bolsing made the 
statement, that in the case of differences between Umney's method 
and theirs, the latter should always be preferred; for they themselves 
admit that with artificial mixtures Umney's method also gives figures 
which agree most satisfactorily. The fact that the results obtained by 
their method agree with those of the process recommended by Thorns 
is not at all convincing, as the latter gives approximate values only 
when the conditions mentioned in the directions are carried out most 
accurately — a matter which is very difficult to accomplish. For practical 
purposes moreover this method generally takes up too much time. 
After all we still believe that the method proposed by Umney, 
modified by us in the above-mentioned manner, is the most practical 
and reliable method for the determination of eugenol. According to 
this process, lo cc oil are shaken for a considerable time with a 5 per 
cent, soda liquor in a burette or cassia flask, and the mixture then 
left standing, but the vessel is occasionally turned lightly round on 
its vertical axis in order that oil drops adhering to the sides of the 
glass may also rise to the surface. The portions of the oil which have 
not combined with alkali are estimated volumetrically, and the eugenol- 
content is ascertained from the difference between the original quantity 
of oil and the non-phenols. In order to avoid all misunderstanding 
we would point out, that we can only guarantee the eugenol-content 
of oils of clove on the basis of the method just described. Further, 
we wish to call particular attention to the fact that it is here a question 
of percentages by volume, although with normal oils of clove the 
difference between percentages by weight and by volume should not 
be very large. 
