PASSAGE 6

Potash (the old name for potassium carbonate) is one of the two alkalis (the other being soda,sodium carbonate) that were used from remote antiquity in the making of glass, and from theearly Middle Ages in the making of soap: the former being the product of heating a mixture ofalkali and sand, the latter a product of alkali and vegetable oil. Their importance in thecommunities of colonial North America need hardly be stressed.