WATER SUPPLY AND PUBLIC HEALTH. 
43 
result ; as Thames water could be retained for the latter. 
The expense attendant upon this change would be very great, 
but it would probably be less than that required for many of 
the proposed schemes. Newcastle-on-Tyne and Gateshead are 
supplied from upland gathering grounds, supplemented when 
necessary with water pumped from the Tyne. A bill, to be 
submitted to Parliament during the coming session, provides 
powers to lay down duplicate mains, with the view of confining 
the Tyne water to the trade supply. 
In the foregoing tabular statement the water is supposed to 
be obtained in three different ways : from wells, springs, and 
galleries driven along the water-bearing strata to intercept the 
subterranean flow of water. It is probable that this last plan 
will in time be extensively adopted. It was first systematically 
used by the late Mr. Easton, in supplying Ramsgate by head- 
ings driven near the chalk cliff, intercepting the water which 
before flowed to the sea. Mr. Barlow proposed to collect the 
chalk-water along the south side of the Thames in a similar 
way ; and Mr. Lucas has recently proposed to use this method 
extensively for the supply of London. The headings driven 
from the sides or bottoms of wells to intercept the water-yielding 
fissures depend upon the same principle ; such are now largely 
adopted. Water is thus mined for , along the lines at which it 
is most likely to occur. 
The abstraction of so large an amount of spring water for the 
supply of London would sensibly diminish the summer flow of 
the streams. This would have to be restored by large com- 
pensation reservoirs in which to store the surplus rainfall. This 
might also in many cases be largely stored in the great natural 
underground reservoirs by carrying down shafts through the 
overlying impervious beds. If sewage can thus be absorbed 
and got rid of (as it has been on a large scale), the same may 
be done with surplus rainfall ; but this should be done before 
the water is polluted. Drainage water on the tertiary beds is 
often turned into the undertying absorbent chalk ; the porous 
beds of the lower greensand and oolites have been used in the 
same way. 
The River Pollution Report refers to many subjects of great 
interest, in addition to those to which we have too briefly 
alluded. One of the most important divisions of the volume 
describes the water supply of provincial towns and villages. 
This brings out most forcibly how large, in all parts of the 
country, is the number of shallow wells which yield impure and 
even dangerous water. Many instances are given in which 
water fit only for irrigation is constantly used for drinking. A 
well in the market-place at Deal has a manure valley fully equal 
to that of average London sewage. 
