I have visited all these places, and made myself acquainted with the works. At Canterbury there are three reservoirs covered in and protected, by a concrete roof and layers of pebbles, both from the summer's heat and the winter's cold. Each reservoir holds 120,000 gallons of water. Adjacent to these reservoirs are others containing pure slaked lime--the so-called 'cream of lime.' These being filled with water, the lime and water are thoroughly mixed by air forced by an engine through apertures in the bottom of the reservoir. The water soon dissolves all the lime it is capable of dissolving. The mechanically suspended lime is then allowed to subside to the bottom, leaving a perfectly transparent lime-water behind. The softening process is this: Into one of the empty reservoirs is introduced a certain quantity of the clear lime-water, and after this about nine times the quantity of the chalk-water. The transparency immediately disappears--the mixture of the two clear liquids becoming thickly turbid, through the precipitation of carbonate of lime. The precipitate is crystalline and heavy, and in about twelve hours a layer of pure white carbonate of lime is formed at the bottom of the reservoir, with a water of extraordinary beauty and purity overhead. A few days ago I pitched some halfpence into a reservoir sixteen feet deep at the Chiltern Hills. This depth hardly dimmed the coin. Had I cast in a pin, it could have been seen at the bottom. By this process of softening, the water is reduced from about seventeen degrees of hardness, to three degrees of hardness. It yields a lather immediately. Its temperature is constant throughout the year. In the hottest summer it is cool, its temperature being twenty degrees above the freezing point; and it does not freeze in winter if conveyed in proper pipes. The reservoirs are covered; a leaf cannot blow into them, and no surface contamination can reach the water. It passes direct from the main into the house tap; no cisterns are employed, and the supply is always fresh and pure. This is the kind of water which is supplied to the fortunate people of Tring, Caterham, and Canterbury. *****