Potash manufacture. Woodcut of a man collecting precipitated solids (potassium hydrogen tartrate) from a wine barrel for use in making potash (potassium carbonate). The solids, known as wine lees, argol or tartar, are formed during wine fermentation. When the argol is heated it forms potash. Potash is used in the manufacture of soap and glass. Image taken from Ortus Sanitatis, a book published in Strasbourg in 1497.