on a water-bath in an accurately weighed platinum dish to dryness and transfer the same to the main portion of the chlorid from the watch glass. In order to obtain the salt free of the corresponding combinations of sodium, barium, calcium, and magnesium, which salts, although soluble in alcohol, may make the salt impure, before weighing, treat the precipitate twice with small quantities of cold water which will dissolve these impurities; evaporate the solution after addition of one cubic centimeter of platinic chlorid nearly to dryness on a water-bath, treat the residue in the same way as given before, add the small quantity of potassium platinochlorid which is hereby obtained together with the main portion to the platinum dish, dry at 130°, and weigh. Only after having been treated in this way may the precipitated potassium platinochlorid be considered absolutely pure. The Stassfurt salts contain magnesia, often in large quantities and as a consequence the potassium platinochlorid precipitated directly is likely to be contaminated therewith. =258. Methods for the Analysis of Carnallit, Kainit, Sylvinit, and Kieserit.=—The chemists of the German Potash Syndicate use the following methods in the analysis of the raw products mentioned above.[207] (1) _Preparation of the Sample._—It is advisable to take from a large well mixed mass at least half a kilogram for the analytical sample and this should be ground to a fine powder in a mill or mortar. (2) _Estimation of the Potash by the Precipitation Method._—In a half liter flask are placed 35.70 grams of kainit or sylvinit, or 30.56 grams of carnallit or bergkieserit, which are boiled with 350 cubic centimeters of water after the addition of ten cubic centimeters of hydrochloric acid. After cooling the flask is filled to the mark with water, well shaken, and its contents filtered. Fifty cubic centimeters of the filtrate are treated in a 200 cubic centimeter flask with a solution of barium chlorid, the flask filled to the mark, well shaken, and its contents filtered. Twenty cubic centimeters of the filtrate, corresponding to 0.3570 or 0.3056 gram of the substance, are treated with five cubic centimeters of platinic chlorid solution and the potassium estimated according to the usual methods.