Wafer Suppli/. 275 



Pumping water from a stream would seem to be too obvious 

 a remedy to need much notice ; yet I may state that a large 

 mansion, tenanted by several families in succession, lost its 

 tenants for lack of good water-supply : until at length, under 

 the advice of the writer, an effectual remedy was found by raising 

 a supply through filtering-beds into a tank from an adjacent and 

 frequently turbid stream. 



Land- Springs. 



Land-spring is a term generally applied to sources of water 

 Avhich are found in or flow from superficial beds of gravel or 

 drift, lying on an impervious substratum. Since many districts 

 throughout England are entirely dependent on such sources for 

 their supply of water they require further notice. .Very many ot 

 our most ancient towns and other places of early habitation are 

 placed on drift-gravel, probably from the facility with which 

 water is thence obtained. The older part of London, and the 

 city of Oxford, on different geological formations, are noteworthy 

 examples of towns so supplied, until they were extended beyond 

 their ancient limits, or until these sources, as is often the case, 

 became tainted by infiltration from sewers, cesspools, and the 

 like. Most of the higher ground on the London clay, such as 

 Hampstead, Highgate, Harrow, Bushey Heath, and the Bagshot 

 district — where a better-defined formation overlies the London 

 clay — are examples of this kind of supply. In the Bagshot 

 sands, in consequence of their great depth and wide develop- 

 ment, by taking advantage of the levels at which water is thrown 

 out by bands of clay alternating with the sand-beds and by 

 turning to account the undulations of surface, large lakes or 

 ponds are formed, such as Virginia Water. At Bear Wood, a 

 dam being thrown across a valley, the water collected in an 

 ornamental lake serves to drive the agricultural and other ma- 

 chinery of the Home Farm, — an example of economising waste 

 water Avhich is worthy of especial notice. In the London and 

 Hampshire Basins this character of supply is not entirely con- 

 fined to the limits of the London clay in situ, but extends to the 

 higher ridges of the chalk, Avhich are frequently capped with 

 traces of the tertiary formations, so that water is frequently 

 retained in gravels by which they are covered or upheld in sur- 

 face-ponds. The chalk district is, therefore, marked by the 

 gathering of the population either on these higher levels or else 

 in the valleys in which run the streams which issue from the 

 subjacent chalk stratum. In the former of these a rigid economy 

 in the use of water is forced on the agricultural and other popu- 

 lation, as, on the failing of the supply, no resource is left but 

 the streams in the vallevs, or very deep wells, from which water 



