174 FRAGMENTS OF SCIENCE. 



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 imme- 

 diately 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 re- 

 duced 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. 



The foregoing article, as far as it relates to the 

 theory which ascribes epidemic disease to the develop- 

 ment of low parasitic life within the human life, was 



