Notes on scientific research. 113 



amounting to 0.58. Marcille, on the whole, regards distillation as superfluous for 

 the purpose of determining the iodine value of liqueurs containing sugar. Some few 

 oils, especially aniseed oil, show e reduction of the iodine value in course of time. 



In any case Marcille opines that the determination of volatile oils is always a very 

 uncertain matter in case one does not possess the oil which was employed for the 

 production of the compound, destined for investigation. 



Finally, X. Rocques 1 ) refers to the papers issued by the committee formed by 

 Rocques, Coudon, Muttelet and Ronnet. Comparative experiments were made on the 

 volumetric method for the determination of the iodine value, recommended by Ronnet, 

 and on the above-mentioned direct weighing method investigated by Muttelet, for the 

 purpose of examining a number of the most generally-known liqueurs. The results can 

 be summed up on the whole as proving that the weighing method can be universally 

 applied, but the iodine-value method only in the case of aniseed oil, whereby the iodine 

 value 1.450 must be taken as a basis and in the case of kummel liqueur, the iodine 

 value 2.400 being the basis employed. 



Most of the best known brands contain more than 0.5 g. of volatile oil per litre, 

 some few, as for instance curacao, even more than 2 g. French vermouth contains 

 so little volatile oil that the determination is impracticable. 



Determination of the, water-content of drugs. — In our last October Report, we referred 

 to the difficulties encountered when determining the water-content of drugs, and which are 

 occasioned by the circumstance that in the methods generally employed for determining 

 moisture, such as the drying closet or the desiccator, not only the water evaporates, 

 but also the volatile oil to a great extent or even entirely which causes the results 

 obtained to be too high. In order to obviate this disadvantage, van Itallie, Kerbosch 

 and Olivier 2 ) recommended the, determination of the moisture as such which can be 

 effected by the distillation-method, according to which the substance to be tested is 

 distilled with liquid paraffine, toluene, xylene, or benzine and the water which is liberated 

 then measured. A. Scholl and R. Strohecker 1 ) proceed exactly in this manner, as they 

 distil the drugs with xylene in addition to 5 per cent, toluene and also measure the 

 moisture which is eliminated. Thereby they arrived at just the same results as the above- 

 mentioned authors who point out that xylene and toluene give the best results; however, 

 neither Scholl nor Strohecker seem to have come across this paper. 



On the determination of the strength of spirits of peppermint, vide page 34 of 

 this Report. 



A process for the determination of the oil content of sandalwood oil is described 

 on page 58 of this Report. 



Acenaphthene-test for distinguishing aliphatic from cyclic aldehydes. — A reaction which 

 might be of use in examining volatile oils refers to the test described by R. de Fazi 3 ), 



-ra 



with acenaphthene (peri-ethylene naphthalene), Ci H 6 ( i ), which is said to allow 



V 2 ) CH 2 / 



to distinguish aliphatic from cyclic aldehydes. He adds 1 cc. of concentrated sulphuric 



acid to a mixture of a few drops of a solution of the test-aldehyde in chloroform and 



l ) Annal.de Chim.anat. 21 (1916), 175; Ann. cles Falsifications 9 (1916), 127; Chem. Zentralbl. 1916, 11.851. 

 — 2 ) Pharm. Weekblad 52 (1915), 205; Report October 1916, 95. — 3 ) Gazz. chim. ital. 46 (1916), I. 334; 

 Chem. Zentralbl. 1916, II. 567. — Journ. Soc. chem. Industrij 35 (1916), 753. 



