— 152 — 



was able in several instances to detect the presence of ethylcitrate by 

 determining the saponification value of the evaporation-residue, and, in 

 the case of two samples, to trace adulteration with terpinyl acetate by 30 

 minutes to 1 hour's saponification. ParYy has extended his work to the 

 determination of the evaporation residue in the saponified oil, on the 

 assumption that in pure bergamot oil this value should approximately equal 

 the evaporation residue of the non-saponified oil, whereas in an oil adul- 

 terated with ethylcitrate this ester is decomposed in the saponification- 

 process and may be removed by shaking with water, for which reason the 

 evaporation residue should be correspondingly less. This determination 

 therefore only confirms the presence of a sparingly volatile ester, the 

 occurrence of which was clearly shown by the saponification value of the 

 evaporation-residue and by the acid value II. Parry affords an additional 

 proof to the same effect by determining the refractometer figure of the 

 oil after evaporating it down to one-tenth of its original weight. 



}. A. Brown 1 ) has worked out a method for determining small quan- 

 tities of essential oil in spices which supports that previously published 

 by himself and Cripps 2 ). The substances which are volatilisable in a current 

 of air between 130 and 140° are conducted trough a combustion tube 

 filled with cupric oxide, burnt up, and the carbonic acid collected and 

 weighed. When the carbon content of the drug in question is known, its 

 essential oil content can be calculated from the ascertained quantity of 

 carbon. In te case of cinnamon oil the average was found to be 80°/ . 



For the purpose of testing the solubility of essential oils, R. Gattefosse 3 ) 

 recommends a method similar to that proposed many years by Dowzard 4 ). 

 According to Gattefosse, water is allowed to drip from a dropping bottle 

 into a mixture of three drops of oil in 30 drops of 93% alcohol until the 

 mixture becomes permanently clouded. The number of drops which has 

 been added to the mixture is the required solubility co-efficient, and is 

 higher in proportion as the oil in question is more readily soluble. The 

 principal difference between Gattefosse's and Dowzard's methods is that 

 in the last-named absolute alcohol is employed. 



Gattefosse further shows how from the solubility co-efficients may be 

 calculated the strength of alcohol corresponding to the mixture of alcohol 

 and water concerned. On the basis of this calculation he indicates for 

 a whole series of co-efficients the quantities and alcoholic strengths 

 required to dissolve 3 drops of each separate oil according to its co-efficient. 



*) Analyst 35 (1910), 392. Quoted from. Chem. Zentralbl. 1910, II. 1168. 



2 ) Comp. Report April 1910, 157. 



3 ) Parfum. moderne 3 (1910), 97. 



±) Chemist and Druggist 53 (1898), 749; also comp. Gildemeister and Hoffmann, Die 

 atherischen die, 2 nd Ed., Vol. I, p. 587. 



