JVater Suppbj. 271 



ment, Avhether such proceeding's have been successful or otherwise, 

 and especiall}' where the animals may on some future occasion 

 offer the opportunity for an examination. 



Clifton, Gloucestershire. 



XXI. — Water- Supply. By the Rev. J. Clutterbuci;. 

 Prize Essay. 



All water-supply, whether surface or subterranean, whether 

 naturally issuing aboveground from springs, or artificially reached 

 by wells or shafts, is derived from the raintall. Therefore, in 

 treating of the possibility of improving the water-supply in rural 

 parishes for agricultural and domestic purposes, the question 

 resolves itself into the economical use or application of quantities 

 which vaiy, but of which the amount may to a certain extent be 

 ascertained. The amount and distribution of rainfall yearly 

 attracts more attention, and many sources of information are open 

 to the public. The tables of Mr. Glaisher and Mr. Symons 

 show an increase of rainfall with the longitude westward, the 

 influence of altitude, and other physical features ; so that in 

 some localities there is such an abundant and continuous rainfall 

 as to exclude them from the scope of such an inquiry as this. 



Though rainfall is reduced to, and treated with reference to, 

 averages, the economical increase of water-supply has rather 

 respect to a minimum, or to quantities, in excess at certain sea- 

 sons, to be made available when the ordinary average supply falls 

 short. Taking Mr. Symons's published averages of rainfall in 

 England at 30 inch* s, by excluding all above 30 inches as 

 beyond the limit of this inquiry the average is reduced to about 

 25 inches, the minimum at any place being 16'91 inches. 



These facts should Ije noted, though the variations in the 

 C|uantity that falls at any given season make it difficult to base 

 any calculation on the gross quantity falling during the year. 

 Subterranean water depends on the quantity percolating below a 

 certain depth ; the gross rainfall has a greater influence on 

 surface supply. The difficulty alluded to is shown in a remark- 

 able manner by the records of Dalton's gauge, kept by Mr. 

 Dickinson, which registers the water percolating 3 feet below 

 the surface. The average rainfall at the same place for 29 years 

 was 22"5, the percolation 7-5 ; the 10 years ending 1863 gave 

 25-8 total fall, percolation only 5 "9 ; showing that in the longer 

 period the average summer rainfall was in arrear and that in 

 winter was in excess, while in the shorter period the case was 

 reversed. 



VQIj, J,— S. S. T 



