502 ECONOMICAL QUESTIONS. CHAP. 



The water obtained by Artesian wells, it must be remembered, 

 falls on the surface of the rock, which, being 'tapped' underground, 

 yields the supply. If the receiving ground be narrow and inter- 

 rupted, as in the case of the Oxford oolite generally, or broken by 

 faults, as most of the oolites are, the underground supply will be 

 very limited, or else veiy unequally distributed here excessive, 

 there scanty. 



Yet, after making these allowances, the process of boring for 

 deep-seated water is much to be advised, the supply being usually 

 constant, the quality good, though commonly a little hard. The 

 enormous quantities of good water daily pumped from the chalk 

 under London the gift of rains and snows on the hills of Herts 

 and Surrey present one of the most impressive~ examples of the 

 process by which nature keeps perpetually full the subterranean 

 rifts and other cavities in the calcareous rock. These cavities 

 are undergoing enlargement by means of the currents occasioned 

 by the powerful steam-pumps, and the reservoir becomes more 

 and more capacious. The interior becomes more and more hollow 

 under London, and more and more water is demanded and ob- 

 tained; yet it is not probable that the bridges will fall in our 

 time, or that the metropolis will ever compel so much water from 

 the shrinking wells as to dispense with the Thames and leave it 

 to be contaminated and productive of disease and death. 



If indeed there should be, according to some popular notions, 

 either a reduction of the annual rainfall, or a diminution of the 

 perennial springs of the Thames, by more rapid discharge of flood- 

 water and more effective surface drainage, some other scheme must 

 be considered. 



The whole supply which now passes by Oxford in ordinary 

 weather (see p. 46), is only equal to the quantity which London 

 consumes ; and water, like coal, is more freely used and wasted 

 than formerly, for old and new purposes, and will be continually 

 in greater and increasing demand for work, health, and ornament, 

 so that the thirsty metropolis will ere long drink up the river. 



Instead of depending on the Thames and its branches, 'new 

 rivers' may have to be brought from distant regions the examples 

 of Manchester and Glasgow may be followed ; and, though not in 

 our days, the slopes of Welsh mountains like Plynlimmon and the 

 JBerwyns may be formed into reservoirs, and the midland counties 



