2 
Arterial Drainage 
the ground, and creates malaria in the neighbourhood. Ague, 
which used to be the common disease of the Fen districts, has, 
since the adoption of an improved system of drainage, almost 
entirely disappeared : its occasional recurrence now only happens 
during droughts in autumn, when the water is dried Up out of the 
ditches, and the sun, acting on the decaying vegetable matter 
thus exposed, creates a malarious atmosphere. 
Avoiding any reference to ordinary under-drainage by pipes, 
and to the improvement and management of tidal streams, and 
other large works which, owing to their magnitude and the great 
number of interests involved, can only be carried out by public 
bodies under the guidance of a Civil Engineer, it is proposed in 
this article to deal with the main drains, ditches, or " sewers," 
Avhich collect the rainfall from the under-drains, and with the 
brooks and smaller water-courses, which receive the outflow of 
the ditches and convey it away to the tidal rivers and estuaries 
— with such arterial drainage, in fact, as is to be found on 
all large estates, the improvement and management of which 
devolves on the landowner and his agent. It is also proposed 
to give in general terms such information on the theory and 
practice of drainage as may be of service to those who constitute 
the various Drainage Boards of the country, in enabling them 
the better to comprehend plans of improvement which may 
from time to time be brought before them ; and to point out 
the various uses which the rainfall may serve before it is. 
allowed finally to leave the land for its ultimate destination, — 
the ocean. 
The question of dealing with water-courses is becoming one 
of growing importance. The higher cultivation of the land on 
the one hand, and the increase of flooding on the other, render 
the enhanced loss from the latter cause so serious as to call for 
interference from the Legislature. 
As each proprietor under-drains his fields, and improves the 
main water-courses through his estate by cutting off bends and 
adapting the form of the channel to the state most conducive to 
a rapid flow of the water, the rainfall is more quickly disposed of, 
and reaches the outfall at a period very much sooner than it was 
able to do previously. Less water therefore remains in the 
soil, and there is no longer a supply to keep up the gradual 
percolation which formerly fed our brooks and springs. Hence 
the alternate floods and droughts which are now so constantly 
occurring. To meet this difficulty it is necessary to adapt the 
channels to receive the extra service required of them in flood- 
time, and to store up the surplus flood-water for provision during 
the time of drought. 
The divided control and jurisdiction, however, over a main 
