Alkaline waters are mineral waters in which there is dissolved sufficient quantities of carbonate or bicarbonate of soda or similar salts to give the water a distinct alkaline taste and reaction. Alkaline waters are found particularly in regions where the rainfall is deficient. The natural rain not being sufficient to dissolve all the soluble matters in the soil, these alkaline bodies, products of decomposition of rocks, accumulate. During periods of heavy rainfalls which frequently occur in such regions large quantities of these alkaline salts go into solution and are carried into the earth. From this source are fed springs and streams which furnish the alkaline waters at intervals between the rains. These alkaline waters are esteemed in some localities for their medicinal properties, but are not suitable for consumption as a beverage. Laxative waters usually contain large quantities of sodium sulphate (Glauber's salts).