A treatise on waterworks for the supply of cities and towns : with a description of the principal geological formations of England as influencing supplies of water ... / by Samuel Hughes.
- Date:
- 1859
Licence: Public Domain Mark
Credit: A treatise on waterworks for the supply of cities and towns : with a description of the principal geological formations of England as influencing supplies of water ... / by Samuel Hughes. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![has shown that the water line in the district between Watford and London has an inclination of about 13 or 14 feet per mile, and that the inclination in the district north of London is only about 10 feet per mile. Mr. Prestwich quotes some observa- tions made by Mr. W. Bland on the height at which water stands in two lines of wells about 6 miles apart, traversing the chalk district between Sittingbourne and Maidstone. Reduc- ing these observations, Mr. Prestwich finds that on one line the inclination of the water line is 47 feet per mile, and on the other 45 feet per mile, or nearly the same. All these in- clinations, both those of Mr. Clutterbuck and Mr. Bland, appear to correspond roughly with the dip of the chalk strata in the respective districts. In some other observations by Mr. Bland, where a diflerence occurs in the water level of 93 feet and 102 feet in distances of less than a mile, Mr. Prestwich says that these probably arise from some local cause. DEPRESSION OF WATER LEVEL IN LONDON WELLS. Mr. Clutterbuck stated, in 1843, that the depression in the centre of London amounted to 50 feet; at the Hampstead Road 30 feet; and at the Zoological Gardens, 25 feet. Mr. David- son, from observations made in 1822, said the water in ten of the principal wells in London then stood at the level of Trinity high water mark. In ] 843, the water did not rise to within 50 feet of that level, thus showing a depression of more than 2 feet per annum. CHALK WELLS. The circumstances under which water is met with in sinking near Watford are thus described by Mr. Stephenson, in his report on the water supply. The valley of the Colne is covered by a bed of alluvial gravel (} diluvial) about 20 feet in thick- ness, and on sinking through this about 5 feet into the chalk, abundant springs of water are met with, which increase in magnitude and force as we descend. Mr. Stephenson then describes two experiments which he](https://iiif.wellcomecollection.org/image/b21988092_0045.jp2/full/800%2C/0/default.jpg)
