THE ANALYST. AUGUST, 1902. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS, HEXABROMIDES OF GLYCERIDES AND FATTY ACIDS. BY JOHN WALKER AND GEORGE WARBURTON. (Read at the Meeting, April 9, 1902.) IN a paper by Hehner and Mitchell, published in the ANALYST of December, 1898, there is given a convenient method for the determination of the hexabromides obtainable from oils and their fatty acids. This was accompanied by some figures obtained by the authors in the course of their investigations. The following table may be of value to those interested in the subject, par- ticularly as some of the figures given refer to oils not hitherto examined in this direction : Kind of Oil. Japan fish .-. Newfoundland cod Shark-liver ... Genuine cod-liver Deodorized fish . . . Sperm ... ... WCale ...... ... ... Seal ... ... Per Cent. Yield of Hexa- bromide from Glyceride of Patty Acids. A ... 21.14 22.07 ... 32.68 30.62 ... 21.22 19.08 ... 35.33 33.76 ... 49.01 52.28 ... 2-61 2-42 ... 3-72 3.69 (stood 48 hours) ... 15.54 16.14 ... 27-54 27-92 - - Rape ... ... ... Linseed (iodine value 184) - - 208) ... ... ... Liquid acids (iodine value Linseed (iodine value 181) 23-14 23.52 Candle-nut ... ... 8.21 7-28 Chinese-wood (1st sample) 0.38 0.39 Safflower . . . ... ... - - 2 9 ,, (2nd sample) none - - Per Cent. Yield of Hexabromide from Fatty Acids. 23.04 23.32 39.1 37-76 12.68 15.08 29.86 30-36 38-42 39.27 2 -05 - 12.38 12.44 19.83 19-93 2-44 3.38 31.31 30.44 30.80 I - 34.9 - 29-06 29.34 11.53 11.23 13-63 The work was carried out in the laboratory of Dr.Lewkowitsch.238 THE ANALYST. DISCUSSIUN. Mr. HEHNER inquired whether Dr. Lewkowitsch (who read the paper in the absence of the authors) could explain why, in some cases, the fatty acids yielded so much smaller percentages of hexabromide than the glycerides. Mr. C. A. MITCHELL said that since the paper by Mr. Hehner and himself, to which reference had been made, he had examined a large number of linseed oils, and almost without exception the quantity of hexabromide yielded was from 23 to 25 per cent. In one case 42 per cent. had been obtained, but he did not know the origin of the oil. He had not been able to reduce the compound, even after treat- ment with zinc for several hours. Dr. LEWKOWITSCH said that the point referred to by Mr. Hehner was a somewhat curious one, and required explanation. He was not himself responsible for the figures, which were simply given as they were obtained in the actual experiments. The collection, however, of individual figures such as theee could not but tend to an increase of knowledge in regard to the individual oils concerned.