and the Storage of Water. 
55 
•crushing ore, pumping, and winding, illustrate of what service 
water may be if properly applied. As an example of the power 
to be utilised on our smaller rivers and water-courses, the case of 
the Wandle, a small tributary of the Thames, with a watershed 
of only 17,605 acres, may be cited — the water from this stream 
driving no less than 38 mills of an aggregate of 781 horse-power. 
Mr. Bailey Denton considers that the drainage off 20,000,000 of 
.acres of this country might be made available to deliver its sur- 
plus water at a mean height of 150 feet, and that a power equal 
to at least half that obtained from the use of coal might be 
secured from this source alone.* 
Mills have had to bear a great deal of undeserved blame for 
causing floods ; but a proper consideration of the subject, and a 
perusal of the evidence given before the Floods Committee of 
the House of Lords, are sufficient to show that, under proper regu- 
lations, there is no reason why mills, with their attendant weirs 
and staunches, should in any way contribute to the flooding of the 
districts above them. On the other hand, credit should be given 
for the good they do by preserving the water and preventing 
the land from being denuded of all its moisture by an over- 
zeal for drainage. A properly constructed weir across a stream 
only affects the land to such a distance as it prevents the side 
drains emptying into the main stream. Parallel drains dis- 
charging below the weir are a simple remedy for this. Mr. 
Abernethy in his evidence, referring to the Thames, says that " he 
does not agree with the sweeping measure of removing all these 
various dams and weirs which at present keep up the surface- 
level ; and considers that their removal, with a deepening of the 
bed of the channel, would allow the river to run in a depressed 
bed considerably below the level of the adjoining lands, and 
during the summer months would act as a great drain to the 
subsoil." In this opinion Mr. Coote and Mr. Grantham entirely 
concurred."!" The most perfect system of drainage in England is 
to be found in the Fens. Here the water is always held up in 
summer, the sluice-gates being opened by the sluice-keepers, 
when necessary, to let off any surplus. In autumn, when from a 
heavy fall of rain and the saturation of the ground a full flow of 
water may be expected, the sluices are opened and the main drains 
partially emptied, so as to be ready to receive the rainfall which 
will reach them from the upper districts in the course of from 24 
hours to two days. The water is then allowed to have free course 
until the flood has passed off, when the " slackers " or draw-doors 
are again closed, and the water is allowed to reach the summer 
* ' The Storage of Water.' By B. Denton. 8pon and Co., 1874. 
t ' House of Lords' Committee on Conservancy Boards, Report and Evidence,' 
1877 ; QQ. 202, 47-i, 475, 542, 553, 645, 812, 816, 907. 
