Treatment of Water to Prevent Corrosion1

Prior to the time when no effort was being made to reduce corrosion in public water supplies, the corrosiveness of the water varied greatly for different cities. The water in some of the supplies was known to be acid, yet in the vast majority of supplies it was alkaline, according to the customary test for alkalinity. There was no very good explanation as to why some of these waters corroded the pipes very much more readily than others. In giving this matter consideration in 1919 and 1920, the equilibriums of certain substances in solution were studied. Where the water was fairly non-corrosive to iron pipes it was found that it was saturated or nearly saturated with calcium carbonate, and where it was corrosive the water was not saturated with this compound. It was only one or two years prior to this that chemists began to give consideration to the hydrogen ion concentration of water and the value of the test had not been demon-