_Potassium Chlorid._—The following process is used for the estimation of potassium and other constituents of the high grade chlorids of commerce. In a half liter flask are placed 7.6405 grams of the finely powdered sample, which is dissolved and made up to the mark. With salts which contain more than half a per cent of sulfuric acid the preliminary conversion of the sulfates into the corresponding chlorin compounds, by precipitation with barium chlorid solution, is necessary. Twenty cubic centimeters of the above solution, corresponding to 0.3056 gram of the salt, are placed in a flat porcelain dish having a diameter of about ten centimeters and, after the addition of five cubic centimeters of the platinic chlorid solution, evaporated on the water-bath with constant stirring until, after cooling, the sirupy liquid passes quickly into a fine crystalline condition. The residue is rubbed into a fine powder with a glass rod, mixed with twenty cubic centimeters of ninety-six per cent alcohol and dried at 120° to a constant weight. It is weighed while warm and brought on a moistened filter with alcohol, care being taken that the liquid does not touch the edge of the filter. The filtration can be carried on under a moderate pressure. The complete washing of the potassium platinochlorid can be easily accomplished upon the filter. The filter and the precipitate, after as much of the alcohol wash has been removed as is possible, are dried at 120° to constant weight and weighed while still warm. One milligram of the potassium platinochlorid thus obtained corresponds to a tenth per cent of potassium chlorid. _Estimation of Sodium Chlorid._—For the estimation of the sodium chlorid which may be present in the potassium chlorid twelve and a half grams of the latter salt are dissolved in a quarter liter flask with twenty-five cubic centimeters of boiling water after the addition of a little potassium carbonate for the purpose of converting the magnesium and calcium compounds into carbonates. After filtration 100 cubic centimeters corresponding to five grams of the salt are evaporated to dryness in a porcelain or platinum dish after the addition of a few drops of concentrated hydrochloric acid in order to convert any calcium carbonate which may be present into chlorid. The residue is gently ignited and weighed. In this mixture of potassium and sodium chlorids the potassium chlorid may be estimated in the usual way and the sodium chlorid determined by difference or the respective proportions of the two bases may be calculated after the determination of the total chlorin by precipitation with a standard solution of silver nitrate.