- 83 - 
tested for their purity by determining the physical constants and the 
sohibility in alcohol The process which they thereby employed does 
not differ in any marked degree from that of Hiibl, which is in use 
for the estimation of the iodine number of fatty oils. The accurately- 
weighed oil was dissolved in 80 per cent, alcohol, and that solution 
mixed with 15 to 2 o cc of an alcoholic solution of iodine and mercuric 
chloride; after standing for exactly three hours, the excess of iodine 
was titrated back with deci-normal solution of sodium hyposulphite. 
Messrs. Sangle-Ferriere and Cuniasse, however, are of opinion 
that the iodine numbers communicated by them can not only be 
used with advantage for the quantitative estimation of essential oils in 
liqueurs or generally in alcoholic solutions, but that they can also 
serve for the identification and detection of adulterations of essential oils. 
Assuming that the above-mentioned method really gives uniform 
^•alues, it is not quite clear how from the iodine number ascertained, 
the content of essential oil of for example a liqueur can be found, 
for it is highly questionable whether the essential oil whose presence is 
suspected by the odour and taste, is the only representative of this 
class of bodies. It may be predicted with certainty that the results, 
in the case of mixtures, cannot be very favourable, as the essential 
oils do not all possess the same capacity of absorbing iodine. If the 
essential oil is to be estimated according to quantity, it would seem 
to us that Mann's method described on page 10 of our Report of 
October 1902, is far more suitable. 
L. Balbiano and V. Paolini^) have made use of an oxidising 
agent which had hitherto been hardly employed at all in the terpene 
chemistry, viz., mercuric acetate. The experiments made by them 
differ in so far from those of Tafel^) — who allowed the same 
compound to act in the heated state in a closed tube on other 
bodies — that a solution of mercuric acetate at ordinary tem- 
perature is allowed to react slowly on hydrocarbons, olefinic phenol 
ethers, etc. We reproduce here briefly the results obtained by this 
method. In the oxidation of pinene with a saturated solution of 
mercuric acetate during 7 to 8 days, there results as reaction -product, 
an almost colourless, thickish oil whose odour reminds of camphor, 
of the formula C^^H^gOg, i. e. a dioxypinene. It has the specific 
gravity 1,069 (o'^) and boils at 5 mm pressure at 145°, at 20 mm 
at 170^ to 171°. Its property of forming on the one hand with 
hydroxylamine an oxime of the melting point 138,5°, with semicarbazide 
^) Journ. de pharm. et de chim. VI. 17 (1903), 169. 
Berliner Berichte 35 (1902), 2995. 
^) Berliner Berichte 25 (1892) 1619. 
6* 
