The destruction of pathogenic bacteria in drinkingwater, by means of calcium hypochlorite was first suggested in 1894 by Traube1, who found that one part of available chlorin in 1,000,000 parts of water would practically sterilize the water in about two hours. This method was applied practically in the Chicago Stock Yards in the fall of 1908; and at about the same time the method was instituted at Boonton in order to purify the drinking-water of Jersey City. This method has since been introduced in many American cities, and the amount of chlorin used has varied from 0.2 part per million to 3.04 parts per million, while the bacterial reduction has varied from 77 per cent, to 99.7 per cent.
METHODS PURSUED IN TREATING THE WATER
The water-supply furnished to Baltimore is obtained by two large impounding reservoirs which collect the water, respectively, of the Gunpowder River and the stream