THE ANALYST. 3 NOTE ON THE EXAMINATION O F SPERM OIL. BY L. MYDDELTON NASH, F.I.C. (Rsad at the Meeting, December 2, 1903.) SPERM oil on saponification yields about 40 per cent. of ether residue, consisting of mixed alcohols, which are completely soluble in absolute alcohol. Mineral oil, as is well known, is practically insoluble therein. But the fact that the unsaponifiable matter from a sample of sperm oil is soluble in alcohol is no proof whatever that the sample is free from mineral oil, as sperm alcohols give ethyl alcohol the property of dissolving mineral oil freely. If rectified spirit be used instead of absolute alcohol, the amount of mineral oil dissolved is very much less. The following table shows the proportions in which mineral oil is soluble in mixtures of sperm alcohols with absolute alcohol and with rectified spirit.Absolute Alcohol, Volumes taken. Sperm Alcohols, Volumes added. Temperature, Fahrenheit. Mineral Oil: Volumes dissolved, using Absolute Alcohol. Mineral Oil, dissolved, using Rectified Spirit, S.G. 0.8345. 100 100 100 100 100 100 0 4 10 40 40 100 70 70 70 $0 100 70 2 4 8 100 175 any amount trace trace 1 18 20 100 The alcohol was measured in a graduated cylinder, the measured sperm alcohols added, and then mineral oil, until the solution, which was at first;, o h r , became turbid on shaking. The mineral oil used was American lubricating oil, specific gravbty 0.905. DISCUSSION. Dr. LEWKOWITSCH said that this paper exemplified the necessity for avoiding the assumption that solubilities determined for one substance would also hold good if another substance was introduced into the solution. A case in which such a mistaken assumption was often made was the extraction with ether of the lead salts of liquid fatty acids in the presence of solid fatty acids, with a view to a quantitative separation.Of course, the lead salts of stearic and other solid fatty acids were practically insoluble in ether, but if the amount of oleic or other less saturated acid were considerable, the dissolved lead salt would exercise in its turn a solvent action on the lead salts of the solid fatty acids. I t is desirable, therefore, that such a test as that described in this paper should not be relied upon alone, but that the unsaponifiable matter shbuld be further differentiated by treatment with acetic anhydride.4 THE ANALYST.Mr. ALLEN said that evidently from the author’s observations it was undesirable to use absolute alcohol, or to use too strong a solution of the sperm alcohol. Of course, the separation could only be regarded as a preliminary one, and, as Dr. Lewkowitsch had pointed out, an absolute differentiation could only be arrived at by acetylating the alcohols. At the same time, there were cases in which that was not possible or desirable, and it was therefore well to know the exact conditions under which such separation as might be possible by alcohol could be best effected. It was frequently necessary to make some separation, even if only rough, of mineral oil from these higher alcohols, and the condition which had been pointed out by the author was one which it was very important to bear in mind. He (Mr. Allen) had been among the early workers on the subject of sperm alcohol, and among the first, he believed, to point out that sperm oil was a liquid wax, and that it contained as much as 40 per cent. of unsaponifiable matter, which unsaponifiable matter consisted of solid higher alcohols, apparently not of the ethylic series. solubility test as final, but the point was one which he had not seen mentioned before, and he thought it worth notice. Many people, he believed, did use absolute alcohol; in fact, he himself did so. In that case mineral oil would not show at all, as it was completely soluble. Mr. NASH agreed with Dr. Lewkowitsch that no one would thipk of taking