288 
Irrigation and ike Storage of Water 
whatever, it would still be easy enough by means of Weirs and 
sluices to keep back a certain head of water in the bed of the 
stream, which at any time could be drawn from for irrigation 
and other objects. Moreover, it was stated in connexion with 
this scheme that a rhine could be cut all round the edge of the 
moor where it abuts on the high land, which would of course get 
filled after heavy rains with discharges from the hill ditches and 
brooks, and that the water there collected might be always 
utilised to irrigate the adjoining parts of the moorland. 
Water Supply for Stock. 
Many farm homesteads in hill districts are badly off 
for drinking water for stock, especially in those localities where 
wells have to be sunk from 200 to 300 feet ere water-bearing 
strata or a spring can be reached. In these cases the cattle and 
horses have to drink out of a pond, while too frequently it is no- 
thing but a cesspool which takes the drainage of the farmyard 
and all its offices. The spoutings of the farm buildings contri- 
bute a great deal to the contents of all such ponds, and by keep- 
ing the water from this source separate the evil might be 
obviated and an ample supply of drinking water for all the stock 
of the farm provided, not only for winter, but the entire year. 
Cisterns are often employed to serve this object, but they 
are seldom large enough to hold a full supply for any great 
length of time, and a large proportion of the surplus water in 
winter still runs to waste. When the largeness of the supply 
from this source is considered, nothing less than a tank or 
reservoir at most farmsteads would be requisite thoroughly to 
carry out the object. As is well known, the rainfall is much 
greater in some districts than it is in others ; but it has been 
calculated that in the Home Counties the fall of rain-water is 
about 4,800 gallons for each 400 square feet of roof surface, and 
that taking the entire kingdom it would be something like 
5,000 gallons for each 500 feet of roof surface. As to the cost 
of tank construction the calculations made by Mr. Love in Yol. 
XX. 1st Series of the Journal (1859) may be quoted, for although 
they applied to the construction of liquid manure tanks, the same 
kind would serve for the storage of drinking water for stock. 
These will be found in the following table for tanks of the 
depth of 1 0 feet, the depth of excavation for which would be 
12 feet. The clay required to pack 4 inches thick behind the 
brickwork is also given, and the number of bricks required for 
the interior, 9 inches thick, with a 4-inch top and a 4-inch 
bottom, and a manhole 3^ feet in diameter. The bottom is 
recommended to be concave, forming a portion of a sphere, 
the radius of curve of which is equal to the diameter of tank 
