The Popular Science Review - 1876 Author:James Samuelson Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Classified according to softness, the waters stand thus :— 1. Rain water 2. Upland surface water 3. Surface water from cultivated 4. Polluted river w... more »ater 5. Spring water 0. Deep-well water 7. Shallow-well water As regards the water supply of London, the Report just published will greatly strengthen the case of those who are discontented with our present supply—not only as to its quality, modes of distribution and control, but also as to its source. It is not pleasant to think of drinking water mixed with sewage, even although the sewage may enter the river miles away, and the water be most efficiently filtered before delivery. To many who read this Report, what may now be only a matter of taste will become a matter of conviction. The Commissioners unhesitatingly condemn the water supplied from the Thames and the Lea ; that supplied by the Kent Waterworks Company to London, from deep wells in the chalk, is good water, its only fault being a high degree of hardness. The New River Company partly derives its supply from springs and wells in the chalk. According to this Report the amount thus obtained is relatively too small to affect the general quality of the water ; but absolutely the supply so obtained is considerable, nearly, 12,000,000 gallons per day. Chalk water is always hard, chiefly from the .presence of bicarbonate of lime. Dr. Clark invented a process by which this " temporary hardness " may be removed, which consists in mixing water saturated with lime with the water to be softened. The excess of carbonic acid, which holds the carbonate of lime in solution in the hard water, is then transferred to the free lime, and the whole falls down as insoluble carbonate of lime. Apart from the advantage of softening the water, this process has other recommen...« less