This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
It is obtained in large quantities at Stassfurt from carnallite, a double chloride of potassium and magnesium, and forms white or colorless, inodorous cubes or quadrangular prisms, which have a saline taste resembling that of table salt, and which are fusible without decomposition. The salt dissolves in 3 parts of cold and a little less than 2 parts of hot water, and is slightly soluble in alcohol, but is insoluble in absolute alcohol. This salt should not be confounded with potassium chlorate, nor with chlorinated potassa. It is largely employed in the manufacture of other potassium compounds, and is a component, however small, of many natural mineral waters.