As gold and silver are both extracted from quartziferous ores by treatment with potassium cyanide solution according to the MacArthur-Forrest process of gold extraction (this Journal, 1890, 267), this electrolytic method should prove very useful.  By electrolyzing the resulting solution a mixture of gold and silver will be deposited upon the cathode, which can then be parted by nitric acid and tested for as described.

DISCUSSION.

The chairman said that there was little doubt but that further investigation into electrolytic methods of chemical analysis would give even more valuable results than those already obtained.  Systematic investigations of the subject, such as have been given by Dr. Kohn, would go far to prove the adaptability of this method as a substitute for or aid in ordinary qualitative examinations.  The remarks of Dr. Kohn respecting quantitative examinations were very interesting, and well worth following up by other practical work.

Professor Campbell Brown said that Dr. Kohn had shown that electricity brought the same kind of elegance, neatness, and simplicity into analysis that it did into lighting and silver plating.

In its applications to the detection of poisons, he understood Dr. Kohn to say that the poisons must first be extracted by chemical means.  That would not be sufficient, and he had no doubt that if the subject was pursued farther they would have a paper from him (Dr. Kohn) some day, indicating that he had obtained arsenic and such poisons without the previous separation of the metal from organic matter.  It was a very great desideratum to have a method for detecting arsenic and separating it from the contents of the stomach and food directly without previous destruction of the organic matter, and he hoped Dr. Kohn would pursue his work in that direction.

Dr. Hurter said he was about to construct a new laboratory, and he would assure them that one of its arrangements would be the installation of electricity, by which to carry out researches similar to those described.  He was very glad to learn that the presence of arsenic, etc., could be readily proved by means of electrolysis.

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